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Sample records for abell cluster supernova

  1. Illuminating a Dark Lens : A Type Ia Supernova Magnified by the Frontier Fields Galaxy Cluster Abell 2744

    NASA Astrophysics Data System (ADS)

    Rodney, Steven A.; Patel, Brandon; Scolnic, Daniel; Foley, Ryan J.; Molino, Alberto; Brammer, Gabriel; Jauzac, Mathilde; Bradač, Maruša; Broadhurst, Tom; Coe, Dan; Diego, Jose M.; Graur, Or; Hjorth, Jens; Hoag, Austin; Jha, Saurabh W.; Johnson, Traci L.; Kelly, Patrick; Lam, Daniel; McCully, Curtis; Medezinski, Elinor; Meneghetti, Massimo; Merten, Julian; Richard, Johan; Riess, Adam; Sharon, Keren; Strolger, Louis-Gregory; Treu, Tommaso; Wang, Xin; Williams, Liliya L. R.; Zitrin, Adi

    2015-09-01

    SN HFF14Tom is a Type Ia SN discovered at z=1.3457+/- 0.0001 behind the galaxy cluster Abell 2744 (z = 0.308). In a cosmology-independent analysis, we find that HFF14Tom is 0.77 ± 0.15 mag brighter than unlensed Type Ia SNe at similar redshift, implying a lensing magnification of {μ }{obs}=2.03+/- 0.29. This observed magnification provides a rare opportunity for a direct empirical test of galaxy cluster lens models. Here we test 17 lens models, 13 of which were generated before the SN magnification was known, qualifying as pure “blind tests.” The models are collectively fairly accurate: 8 of the models deliver median magnifications that are consistent with the measured μ to within 1σ. However, there is a subtle systematic bias: the significant disagreements all involve models overpredicting the magnification. We evaluate possible causes for this mild bias, and find no single physical or methodological explanation to account for it. We do find that model accuracy can be improved to some extent with stringent quality cuts on multiply imaged systems, such as requiring that a large fraction have spectroscopic redshifts. In addition to testing model accuracies as we have done here, Type Ia SN magnifications could also be used as inputs for future lens models of Abell 2744 and other clusters, providing valuable constraints in regions where traditional strong- and weak-lensing information is unavailable.

  2. The X-ray cluster Abell 744

    NASA Technical Reports Server (NTRS)

    Kurtz, M. J.; Huchra, J. P.; Beers, T. C.; Geller, M. J.; Gioia, I. M.

    1985-01-01

    X-ray and optical observations of the cluster of galaxies Abell 744 are presented. The X-ray flux (assuming H(0) = 100 km/s per Mpc) is about 9 x 10 to the 42nd erg/s. The X-ray source is extended, but shows no other structure. Photographic photometry (in Kron-Cousins R), calibrated by deep CCD frames, is presented for all galaxies brighter than 19th magnitude within 0.75 Mpc of the cluster center. The luminosity function is normal, and the isopleths show little evidence of substructure near the cluster center. The cluster has a dominant central galaxy, which is classified as a normal brightest-cluster elliptical on the basis of its luminosity profile. New redshifts were obtained for 26 galaxies in the vicinity of the cluster center; 20 appear to be cluster members. The spatial distribution of redshifts is peculiar; the dispersion within the 150 kpc core radius is much greater than outside. Abell 744 is similar to the nearby cluster Abell 1060.

  3. Spectroscopic Studies of Abell Clusters

    NASA Astrophysics Data System (ADS)

    Way, Michael Joseph

    The objectives of this work are to use spectroscopic techniques to accurately categorize galaxies as either HII region star forming galaxies or as Active Galactic Nuclei powered via a black hole, and to use radial velocities and projected positions of galaxies in clusters to obtain the total cluster mass and its distribution. The masses and distributions compare well to X-ray mass measurements. The commonly used Dressler, A., Thompson, I. & Shectman, S. 1985, ApJ, 288, 481 technique for discriminating between Active Galactic Nuclei and HII region galaxies uses the measurement of the equivalent width of the emission lines (OII) 3727 A, H/beta, and (OIII) 5007 A. High quality spectra from 42 galaxies were taken and it is shown that their method is not capable of distinguishing between Active Galactic Nuclei and HII region galaxies. The emission line flux from H/beta, (OIII) 5007 A, (OI) 6300 A, Hα, (NII) 6583 A, and (SII) 6716+6731 A in combination with the method of Veilleux, S. & Osterbrock, D. E. 1987, ApJS, 63, 295 must be used to accurately distinguish between Active Galactic Nuclei and HII region galaxies. Galaxy radial velocities from spectroscopic data and their projected 2-D positions in clusters are used to obtain robust estimates of the total mass and mass distribution in two clusters. The total mass is calculated using the Virial theorem after removing substructure. The mass distribution is estimated via several robust statistical tests for 1-D, 2-D and 3-D structure. It is shown that the derived mass estimates agree well with those found independently from hot X-ray gas emission in clusters.

  4. The cluster of galaxies Abell 376

    NASA Astrophysics Data System (ADS)

    Proust, D.; Capelato, H. V.; Hickel, G.; Sodré, L., Jr.; Lima Neto, G. B.; Cuevas, H.

    2003-08-01

    We present a dynamical analysis of the galaxy cluster Abell 376 based on a set of 73 velocities, most of them measured at Pic du Midi and Haute-Provence observatories and completed with data from the literature. Data on individual galaxies are presented and the accuracy of the determined velocities is discussed as well as some properties of the cluster. We obtained an improved mean redshift value z = 0.0478+0.005-0.006 and velocity dispersion sigma = 852+120-76 km s-1. Our analysis indicates that inside a radius of ~ 900 h70-1 kpc ( ~ 15 arcmin) the cluster is well relaxed without any remarkable features and the X-ray emission traces fairly well the galaxy distribution. A possible substructure is seen at 20 arcmin from the centre towards the Southwest direction, but is not confirmed by the velocity field. This SW clump is, however, kinematically bound to the main structure of Abell 376. A dense condensation of galaxies is detected at 46 arcmin (projected distance 2.6 h70-1 Mpc) from the centre towards the Northwest and analysis of the apparent luminosity distribution of its galaxies suggests that this clump is part of the large scale structure of Abell 376. X-ray spectroscopic analysis of ASCA data resulted in a temperature kT = 4.3 +/- 0.4 keV and metal abundance Z = 0.32 +/- 0.08 Zsun. The velocity dispersion corresponding to this temperature using the TX-sigma scaling relation is in agreement with the measured galaxies velocities. Based on observations made Haute-Provence and Pic du Midi Observatories (France). Table 1 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/407/31

  5. Uniform Contribution of Supernova Explosions to the Chemical Enrichment of Abell 3112 out to R 200

    NASA Astrophysics Data System (ADS)

    Ezer, Cemile; Bulbul, Esra; Nihal Ercan, E.; Smith, Randall K.; Bautz, Mark W.; Loewenstein, Mike; McDonald, Mike; Miller, Eric D.

    2017-02-01

    The spatial distribution of the metals residing in the intra-cluster medium (ICM) of galaxy clusters records all the information on a cluster’s nucleosynthesis and chemical enrichment history. We present measurements from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out to its virial radius (∼1470 kpc). We find that the ratio of the observed supernova type Ia explosions to the total supernova explosions has a uniform distribution at a level of 12%–16% out to the cluster’s virial radius. The observed fraction of type Ia supernova explosions is in agreement with the corresponding fraction found in our Galaxy and the chemical enrichment of our Galaxy. The non-varying supernova enrichment suggests that the ICM in cluster outskirts was enriched by metals at an early stage before the cluster itself was formed during a period of intense star formation activity. Additionally, we find that the 2D delayed detonation model CDDT produce significantly worse fits to the X-ray spectra compared to simple 1D W7 models. This is due to the relative overestimate of Si, and the underestimate of Mg in these models with respect to the measured abundances.

  6. The cluster Abell 780: an optical view

    NASA Astrophysics Data System (ADS)

    Durret, F.; Slezak, E.; Adami, C.

    2009-11-01

    Context: The Abell 780 cluster, better known as the Hydra A cluster, has been thouroughly analyzed in X-rays. However, little is known about its optical properties. Aims: We propose to derive the galaxy luminosity function (GLF) in this apparently relaxed cluster and to search for possible environmental effects by comparing the GLFs in various regions and by looking at the galaxy distribution at large scale around Abell 780. Methods: Our study is based on optical images obtained with the ESO 2.2m telescope and WFI camera in the B and R bands, covering a total region of 67.22 × 32.94 arcmin^2, or 4.235 × 2.075 Mpc2 for a cluster redshift of 0.0539. Results: In a region of 500 kpc radius around the cluster center, the GLF in the R band shows a double structure, with a broad and flat bright part and a flat faint end that can be fit by a power law with an index α ~ - 0.85 ± 0.12 in the 20.25 ≤ R ≤ 21.75 interval. If we divide this 500 kpc radius region in north+south or east+west halves, we find no clear difference between the GLFs in these smaller regions. No obvious large-scale structure is apparent within 5 Mpc from the cluster, based on galaxy redshifts and magnitudes collected from the NED database in a much larger region than that covered by our data, suggesting that there is no major infall of material in any preferential direction. However, the Serna-Gerbal method reveals a gravitationally bound structure of 27 galaxies, which includes the cD, and of a more strongly gravitationally bound structure of 14 galaxies. Conclusions: These optical results agree with the overall relaxed structure of Abell 780 previously derived from X-ray analyses. Based on observations obtained at the European Southern Observatory, program ESO 68.A-0084(A), P. I. E. Slezak. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics

  7. The clusters Abell 222 and Abell 223: a multi-wavelength view

    NASA Astrophysics Data System (ADS)

    Durret, F.; Laganá, T. F.; Adami, C.; Bertin, E.

    2010-07-01

    Context. The Abell 222 and 223 clusters are located at an average redshift z ~ 0.21 and are separated by 0.26 deg. Signatures of mergers have been previously found in these clusters, both in X-rays and at optical wavelengths, thus motivating our study. In X-rays, they are relatively bright, and Abell 223 shows a double structure. A filament has also been detected between the clusters both at optical and X-ray wavelengths. Aims: We analyse the optical properties of these two clusters based on deep imaging in two bands, derive their galaxy luminosity functions (GLFs) and correlate these properties with X-ray characteristics derived from XMM-Newton data. Methods: The optical part of our study is based on archive images obtained with the CFHT Megaprime/Megacam camera, covering a total region of about 1 deg2, or 12.3 × 12.3 Mpc2 at a redshift of 0.21. The X-ray analysis is based on archive XMM-Newton images. Results: The GLFs of Abell 222 in the g' and r' bands are well fit by a Schechter function; the GLF is steeper in r' than in g'. For Abell 223, the GLFs in both bands require a second component at bright magnitudes, added to a Schechter function; they are similar in both bands. The Serna & Gerbal method allows to separate well the two clusters. No obvious filamentary structures are detected at very large scales around the clusters, but a third cluster at the same redshift, Abell 209, is located at a projected distance of 19.2 Mpc. X-ray temperature and metallicity maps reveal that the temperature and metallicity of the X-ray gas are quite homogeneous in Abell 222, while they are very perturbed in Abell 223. Conclusions: The Abell 222/Abell 223 system is complex. The two clusters that form this structure present very different dynamical states. Abell 222 is a smaller, less massive and almost isothermal cluster. On the other hand, Abell 223 is more massive and has most probably been crossed by a subcluster on its way to the northeast. As a consequence, the

  8. The magnitude-redshift relation for 561 Abell clusters

    NASA Technical Reports Server (NTRS)

    Postman, M.; Huchra, J. P.; Geller, M. J.; Henry, J. P.

    1985-01-01

    The Hubble diagram for the 561 Abell clusters with measured redshifts has been examined using Abell's (1958) corrected photo-red magnitudes for the tenth-ranked cluster member (m10). After correction for the Scott effect and K dimming, the data are in good agreement with a linear magnitude-redshift relation with a slope of 0.2 out to z = 0.1. New redshift data are also presented for 20 Abell clusters. Abell's m10 is suitable for redshift estimation for clusters with m10 of no more than 16.5. At fainter m10, the number of foreground galaxies expected within an Abell radius is large enough to make identification of the tenth-ranked galaxy difficult. Interlopers bias the estimated redshift toward low values at high redshift. Leir and van den Bergh's (1977) redshift estimates suffer from this same bias but to a smaller degree because of the use of multiple cluster parameters. Constraints on deviations of cluster velocities from the mean cosmological flow require greater photometric accuracy than is provided by Abell's m10 magnitudes.

  9. A 1400-MHz survey of 1478 Abell clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Owen, F. N.; White, R. A.; Hilldrup, K. C.; Hanisch, R. J.

    1982-01-01

    Observations of 1478 Abell clusters of galaxies with the NRAO 91-m telescope at 1400 MHz are reported. The measured beam shape was deconvolved from the measured source Gaussian fits in order to estimate the source size and position angle. All detected sources within 0.5 corrected Abell cluster radii are listed, including the cluster number, richness class, distance class, magnitude of the tenth brightest galaxy, redshift estimate, corrected cluster radius in arcmin, right ascension and error, declination and error, total flux density and error, and angular structure for each source.

  10. Merger shocks in Abell 3667 and the Cygnus A cluster

    NASA Astrophysics Data System (ADS)

    Sarazin, C. L.; Finoguenov, A.; Wik, D. R.

    2013-04-01

    We present new XMM-Newton observations of the northwest (NW) radio relic region in the cluster Abell 3667. We detect a jump in the X-ray surface brightness and X-ray temperature at the sharp outer edge of the radio relic which indicate that this is the location of a merger shock with a Mach number of about 2. Comparing the radio emission to the shock properties implies that approximately 0.2% of the dissipated shock kinetic energy goes into accelerating relativistic electrons. This is an order of magnitude smaller than the efficiency of shock acceleration in many Galactic supernova remnants, which may be due to the lower Mach numbers of cluster merger shocks. The X-ray and radio properties indicate that the magnetic field strength in the radio relic is ⪆ 3 μG, which is a very large field at a projected distance of ˜ 2.2 Mpc from the center of a cluster. The radio spectrum is relatively flat at the shock, and steepens dramatically with distance behind the shock. This is consistent with radiative losses by the electrons and the post-shock speed determined from the X-ray properties. The Cygnus A radio source is located in a merging cluster of galaxies. This appears to be an early-stage merger. Our recent Suzaku observation confirm the presence of a hot region between the two subclusters which agrees with the predicted shocked region. The high spectral resolution of the CCDs on Suzaku allowed us to measure the radial component of the merger velocity, Δ v_r ≈ 2650 km s-1.

  11. Non-thermal Hard X-Ray Emission from Coma and Several Abell Clusters

    SciTech Connect

    Correa, C

    2004-02-05

    We report results of hard X-Ray observations of the clusters Coma, Abell 496, Abell754, Abell 1060, Abell 1367, Abell2256 and Abell3558 using RXTE data from the NASA HEASARC public archive. Specifically we searched for clusters with hard x-ray emission that can be fitted by a power law because this would indicate that the cluster is a source of non-thermal emission. We are assuming the emission mechanism proposed by Vahk Petrosian where the inter cluster space contains clouds of relativistic electrons that by themselves create a magnetic field and emit radio synchrotron radiation. These relativistic electrons Inverse-Compton scatter Microwave Background photons up to hard x-ray energies. The clusters that were found to be sources of non-thermal hard x-rays are Coma, Abell496, Abell754 and Abell 1060.

  12. The nearby Abell clusters. III - Luminosity functions for eight rich clusters

    NASA Technical Reports Server (NTRS)

    Oegerle, William R.; Hoessel, John G.

    1989-01-01

    Red photographic data on eight rich Abell clusters are combined with previous results on four other Abell clusters to study the luminosity functions of the clusters. The results produce a mean value of the characteristic galaxy magnitude (M asterisk) that is consistent with previous results. No relation is found between the magnitude of the first-ranked cluster galaxy and M asterisk, suggesting that the value of M asterisk is not changed by dynamical evolution. The faint ends of the luminosity functions for many of the clusters are quite flat, validating the nonuniversality in the parametrization of Schechter (1976) functions for rich clusters of galaxies.

  13. The nearby Abell clusters. III. Luminosity functions for eight rich clusters

    SciTech Connect

    Oegerle, W.R.; Hoessel, J.G. Washburn Observatory, Madison, WI )

    1989-11-01

    Red photographic data on eight rich Abell clusters are combined with previous results on four other Abell clusters to study the luminosity functions of the clusters. The results produce a mean value of the characteristic galaxy magnitude (M asterisk) that is consistent with previous results. No relation is found between the magnitude of the first-ranked cluster galaxy and M asterisk, suggesting that the value of M asterisk is not changed by dynamical evolution. The faint ends of the luminosity functions for many of the clusters are quite flat, validating the nonuniversality in the parametrization of Schechter (1976) functions for rich clusters of galaxies. 40 refs.

  14. Analysis of LAC Observations of Clusters of Galaxies and Supernova Remnants

    NASA Technical Reports Server (NTRS)

    Hughes, J.

    1996-01-01

    The following publications are included and serve as the final report: The X-ray Spectrum of Abell 665; Clusters of Galaxies; Ginga Observation of an Oxygen-rich Supernova Remnant; Ginga Observations of the Coma Cluster and Studies of the Spatial Distribution of Iron; A Measurement of the Hubble Constant from the X-ray Properties and the Sunyaev-Zel'dovich Effect of Abell 2218; Non-polytropic Model for the Coma Cluster; and Abundance Gradients in Cooling Flow Clusters: Ginga LAC (Large Area Counter) and Einstein SSS (Solid State Spectrometer) Spectra of A496, A1795, A2142, and A2199.

  15. Giant ringlike radio structures around galaxy cluster Abell 3376.

    PubMed

    Bagchi, Joydeep; Durret, Florence; Neto, Gastão B Lima; Paul, Surajit

    2006-11-03

    In the current paradigm of cold dark matter cosmology, large-scale structures are assembling through hierarchical clustering of matter. In this process, an important role is played by megaparsec (Mpc)-scale cosmic shock waves, arising in gravity-driven supersonic flows of intergalactic matter onto dark matter-dominated collapsing structures such as pancakes, filaments, and clusters of galaxies. Here, we report Very Large Array telescope observations of giant ( approximately 2 Mpc by 1.6 Mpc), ring-shaped nonthermal radio-emitting structures, found at the outskirts of the rich cluster of galaxies Abell 3376. These structures may trace the elusive shock waves of cosmological large-scale matter flows, which are energetic enough to power them. These radio sources may also be the acceleration sites where magnetic shocks are possibly boosting cosmic-ray particles with energies of up to 10(18) to 10(19) electron volts.

  16. The Distribution of Dark and Luminous Matter in the Galaxy Cluster Merger Abell 2146

    NASA Astrophysics Data System (ADS)

    King, Lindsay; Clowe, Douglas; Coleman, Joseph E.; Russell, Helen; Santana, Rebecca; White, Jacob; Canning, Rebecca; Deering, Nicole; Fabian, Andrew C.; Lee, Brandyn; Li, Baojiu; McNamara, Brian R.

    2017-01-01

    Abell 2146 (z = 0.232) consists of two galaxy clusters undergoing a major merger, presenting two large shock fronts on Chandra X-ray Observatory maps. These observations are consistent with a collision close to the plane of the sky, caught soon after first core passage. Here we outline the weak gravitational lensing analysis of the total mass in the system, using the distorted shapes of distant galaxies seen with Hubble Space Telescope. The highest peak in the mass reconstruction is centred on the brightest cluster galaxy in Abell 2146-A. The mass associated with Abell 2146-B is more extended. The best-fitting mass model with two components has a mass ratio of ~3:1 for the two clusters. From the weak lensing analysis, Abell 2146-A is the primary halo component, and the origin of the apparent discrepancy with the X-ray analysis where Abell 2146-B is the primary halo will be discussed.

  17. THE GALAXY POPULATION OF LOW-REDSHIFT ABELL CLUSTERS

    SciTech Connect

    Barkhouse, Wayne A.; Yee, H. K. C.; Lopez-Cruz, Omar E-mail: hyee@astro.utoronto.c

    2009-10-01

    We present a study of the luminosity and color properties of galaxies selected from a sample of 57 low-redshift Abell clusters. We utilize the non-parametric dwarf-to-giant ratio (DGR) and the blue galaxy fraction (f{sub b} ) to investigate the clustercentric radial-dependent changes in the cluster galaxy population. Composite cluster samples are combined by scaling the counting radius by r {sub 200} to minimize radius selection bias. The separation of galaxies into a red and blue population was achieved by selecting galaxies relative to the cluster color-magnitude relation. The DGR of the red and blue galaxies is found to be independent of cluster richness (B {sub gc}), although the DGR is larger for the blue population at all measured radii. A decrease in the DGR for the red and red+blue galaxies is detected in the cluster core region, while the blue galaxy DGR is nearly independent of radius. The f{sub b} is found not to correlate with B {sub gc}; however, a steady decline toward the inner-cluster region is observed for the giant galaxies. The dwarf galaxy f{sub b} is approximately constant with clustercentric radius except for the inner-cluster core region where f{sub b} decreases. The clustercentric radial dependence of the DGR and the galaxy blue fraction indicates that it is unlikely that a simple scenario based on either pure disruption or pure fading/reddening can describe the evolution of infalling dwarf galaxies; both outcomes are produced by the cluster environment.

  18. The merging cluster of galaxies Abell 3376: an optical view

    NASA Astrophysics Data System (ADS)

    Durret, F.; Perrot, C.; Lima Neto, G. B.; Adami, C.; Bertin, E.; Bagchi, J.

    2013-12-01

    Context. The cluster Abell 3376 is a merging cluster of galaxies at redshift z = 0.046. It is famous mostly for its giant radio arcs, and shows an elongated and highly substructured X-ray emission, but has not been analysed in detail at optical wavelengths. Aims: To improve our understanding of the effects of the major cluster merger on the galaxy properties, we analyse the galaxy luminosity function (GLF) in the B band in several regions as well as the dynamical properties of the substructures. Methods: We have obtained wide field images of Abell 3376 in the B band and derive the GLF applying a statistical subtraction of the background in three regions: a circle of 0.29 deg radius (1.5 Mpc) encompassing the whole cluster, and two circles centred on each of the two brightest galaxies (BCG2, northeast, coinciding with the peak of X-ray emission, and BCG1, southwest) of radii 0.15 deg (0.775 Mpc). We also compute the GLF in the zone around BCG1, which is covered by the WINGS survey in the B and V bands, by selecting cluster members in the red sequence in a (B - V) versus V diagram. Finally, we discuss the dynamical characteristics of the cluster implied by an analysis based on the Serna & Gerbal (SG) method. Results: The GLFs are not well fit by a single Schechter function, but satisfactory fits are obtained by summing a Gaussian and a Schechter function. The GLF computed by selecting galaxies in the red sequence in the region surrounding BCG1 can also be fit by a Gaussian plus a Schechter function. An excess of galaxies in the brightest bins is detected in the BCG1 and BCG2 regions. The dynamical analysis based on the SG method shows the existence of a main structure of 82 galaxies that can be subdivided into two main substructures of 25 and six galaxies. A smaller structure of six galaxies is also detected. Conclusions: The B band GLFs of Abell 3376 are clearly perturbed, as already found in other merging clusters. The dynamical properties are consistent with the

  19. Chandra Observation of Abell 1142: A Cool-core Cluster Lacking a Central Brightest Cluster Galaxy?

    NASA Astrophysics Data System (ADS)

    Su, Yuanyuan; Buote, David A.; Gastaldello, Fabio; van Weeren, Reinout

    2016-04-01

    Abell 1142 is a low-mass galaxy cluster at low redshift containing two comparable brightest cluster galaxies (BCGs) resembling a scaled-down version of the Coma Cluster. Our Chandra analysis reveals an X-ray emission peak, roughly 100 kpc away from either BCG, which we identify as the cluster center. The emission center manifests itself as a second beta-model surface brightness component distinct from that of the cluster on larger scales. The center is also substantially cooler and more metal-rich than the surrounding intracluster medium (ICM), which makes Abell 1142 appear to be a cool-core cluster. The redshift distribution of its member galaxies indicates that Abell 1142 may contain two subclusters, each of which contain one BCG. The BCGs are merging at a relative velocity of ≈1200 km s-1. This ongoing merger may have shock-heated the ICM from ≈2 keV to above 3 keV, which would explain the anomalous LX-TX scaling relation for this system. This merger may have displaced the metal-enriched “cool core” of either of the subclusters from the BCG. The southern BCG consists of three individual galaxies residing within a radius of 5 kpc in projection. These galaxies should rapidly sink into the subcluster center due to the dynamical friction of a cuspy cold dark matter halo.

  20. CHANDRA OBSERVATION OF ABELL 1142: A COOL-CORE CLUSTER LACKING A CENTRAL BRIGHTEST CLUSTER GALAXY?

    SciTech Connect

    Su, Yuanyuan; Weeren, Reinout van; Buote, David A.; Gastaldello, Fabio

    2016-04-10

    Abell 1142 is a low-mass galaxy cluster at low redshift containing two comparable brightest cluster galaxies (BCGs) resembling a scaled-down version of the Coma Cluster. Our Chandra analysis reveals an X-ray emission peak, roughly 100 kpc away from either BCG, which we identify as the cluster center. The emission center manifests itself as a second beta-model surface brightness component distinct from that of the cluster on larger scales. The center is also substantially cooler and more metal-rich than the surrounding intracluster medium (ICM), which makes Abell 1142 appear to be a cool-core cluster. The redshift distribution of its member galaxies indicates that Abell 1142 may contain two subclusters, each of which contain one BCG. The BCGs are merging at a relative velocity of ≈1200 km s{sup −1}. This ongoing merger may have shock-heated the ICM from ≈2 keV to above 3 keV, which would explain the anomalous L{sub X}–T{sub X} scaling relation for this system. This merger may have displaced the metal-enriched “cool core” of either of the subclusters from the BCG. The southern BCG consists of three individual galaxies residing within a radius of 5 kpc in projection. These galaxies should rapidly sink into the subcluster center due to the dynamical friction of a cuspy cold dark matter halo.

  1. The merging cluster Abell 1758: an optical and dynamical view

    NASA Astrophysics Data System (ADS)

    Monteiro-Oliveira, Rogerio; Serra Cypriano, Eduardo; Machado, Rubens; Lima Neto, Gastao B.

    2015-08-01

    The galaxy cluster Abell 1758-North (z=0.28) is a binary system composed by the sub-structures NW and NE. This is supposed to be a post-merging cluster due to observed detachment between the NE BCG and the respective X-ray emitting hot gas clump in a scenario very close to the famous Bullet Cluster. On the other hand, the projected position of the NW BCG coincides with the local hot gas peak. This system was been targeted previously by several studies, using multiple wavelengths and techniques, but there is still no clear picture of the scenario that could have caused this unusual configuration. To help solving this complex puzzle we added some pieces: firstly, we have used deep B, RC and z' Subaru images to perform both weak lensing shear and magnification analysis of A1758 (including here the South component that is not in interaction with A1758-North) modeling each sub-clump as an NFW profile in order to constrain masses and its center positions through MCMC methods; the second piece is the dynamical analysis using radial velocities available in the literature (143) plus new Gemini-GMOS/N measurements (68 new redshifts).From weak lensing we found that independent shear and magnification mass determinations are in excellent agreement between them and combining both we could reduce mass error bar by ~30% compared to shear alone. By combining this two weak-lensing probes we found that the position of both Northern BCGs are consistent with the masses centers within 2σ and and the NE hot gas peak to be offseted of the respective mass peak (M200=5.5 X 1014 M⊙) with very high significance. The most massive structure is NW (M200=7.95 X 1014 M⊙ ) where we observed no detachment between gas, DM and BCG.We have calculated a low line-of-sight velocity difference (<300 km/s) between A1758 NW and NE. We have combined it with the projected velocity of 1600 km/s which was estimated by previous X-ray analysis (David & Kempner 2004) and we have obtained a small angle between

  2. Narrow-angle tail radio sources and the distribution of galaxy orbits in Abell clusters

    NASA Technical Reports Server (NTRS)

    O'Dea, Christopher P.; Sarazin, Craig L.; Owen, Frazer N.

    1987-01-01

    The present data on the orientations of the tails with respect to the cluster centers of a sample of 70 narrow-angle-tail (NAT) radio sources in Abell clusters show the distribution of tail angles to be inconsistent with purely radial or circular orbits in all the samples, while being consistent with isotropic orbits in (1) the whole sample, (2) the sample of NATs far from the cluster center, and (3) the samples of morphologically regular Abell clusters. Evidence for very radial orbits is found, however, in the sample of NATs near the cluster center. If these results can be generalized to all cluster galaxies, then the presence of radial orbits near the center of Abell clusters suggests that violent relaxation may not have been fully effective even within the cores of the regular clusters.

  3. Angular cross-relations of Abell clusters in different distance classes

    NASA Technical Reports Server (NTRS)

    Szalay, A. S.; Hollosi, J.; Toth, G.

    1989-01-01

    The angular autocorrelation and cross-correlation functions of the D = 1 ... 4, D = 5, and D = 6 distance class Abell clusters are estimated. There is a strong anticorrelation between the most distant D = 6 and the closest D = 1 ... 4 subsamples. It is suggested that an artifact of the cluster identification process presumably due to the finite angular size of the cluster. This anticorrelation seems to contradict some recent estimations of projection contaminations in the Abell catalog. The angular proximity of a foreground cluster may have caused a background cluster not to be counted as it was thought to be a subcluster or it was erroneously assigned to a nearer distance class.

  4. A weak-lensing analysis of the Abell 383 cluster

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Radovich, M.; Grado, A.; Puddu, E.; Romano, A.; Limatola, L.; Fu, L.

    2011-05-01

    Aims: We use deep CFHT and SUBARU uBVRIz archival images of the Abell 383 cluster (z = 0.187) to estimate its mass by weak-lensing. Methods: To this end, we first use simulated images to check the accuracy provided by our Kaiser-Squires-Broadhurst (KSB) pipeline. These simulations include shear testing programme (STEP) 1 and 2 simulations, as well as more realistic simulations of the distortion of galaxy shapes by a cluster with a Navarro-Frenk-White (NFW) profile. From these simulations we estimate the effect of noise on shear measurement and derive the correction terms. The R-band image is used to derive the mass by fitting the observed tangential shear profile with an NFW mass profile. Photometric redshifts are computed from the uBVRIz catalogs. Different methods for the foreground/background galaxy selection are implemented, namely selection by magnitude, color, and photometric redshifts, and the results are compared. In particular, we developed a semi-automatic algorithm to select the foreground galaxies in the color-color diagram, based on the observed colors. Results: Using color selection or photometric redshifts improves the correction of dilution from foreground galaxies: this leads to higher signals in the inner parts of the cluster. We obtain a cluster mass Mvir = 7.5+2.7_{-1.9 × 1014} M⊙: this value is 20% higher than previous estimates and is more consistent the mass expected from X-ray data. The R-band luminosity function of the cluster is computed and gives a total luminosity Ltot = (2.14 ± 0.5) × 1012 L⊙ and a mass-to-luminosity ratio M/L 300 M⊙/L⊙. Based on: data collected with the Subaru Telescope (University of Tokyo) and obtained from the SMOKA, which is operated by the Astronomy Data Center, National Astronomical Observatory of Japan; observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada

  5. MUSE observations of the lensing cluster Abell 1689

    NASA Astrophysics Data System (ADS)

    Bina, D.; Pelló, R.; Richard, J.; Lewis, J.; Patrício, V.; Cantalupo, S.; Herenz, E. C.; Soto, K.; Weilbacher, P. M.; Bacon, R.; Vernet, J. D. R.; Wisotzki, L.; Clément, B.; Cuby, J. G.; Lagattuta, D. J.; Soucail, G.; Verhamme, A.

    2016-05-01

    Context. This paper presents the results obtained with the Multi Unit Spectroscopic Explorer (MUSE) for the core of the lensing cluster Abell 1689, as part of MUSE's commissioning at the ESO Very Large Telescope. Aims: Integral-field observations with MUSE provide a unique view of the central 1 × 1 arcmin2 region at intermediate spectral resolution in the visible domain, allowing us to conduct a complete census of both cluster galaxies and lensed background sources. Methods: We performed a spectroscopic analysis of all sources found in the MUSE data cube. Two hundred and eighty-two objects were systematically extracted from the cube based on a guided-and-manual approach. We also tested three different tools for the automated detection and extraction of line emitters. Cluster galaxies and lensed sources were identified based on their spectral features. We investigated the multiple-image configuration for all known sources in the field. Results: Previous to our survey, 28 different lensed galaxies displaying 46 multiple images were known in the MUSE field of view, most of them were detected through photometric redshifts and lensing considerations. Of these, we spectroscopically confirm 12 images based on their emission lines, corresponding to 7 different lensed galaxies between z = 0.95 and 5.0. In addition, 14 new galaxies have been spectroscopically identified in this area thanks to MUSE data, with redshifts ranging between 0.8 and 6.2. All background sources detected within the MUSE field of view correspond to multiple-imaged systems lensed by A1689. Seventeen sources in total are found at z ≥ 3 based on their Lyman-α emission, with Lyman-α luminosities ranging between 40.5 ≲ log (Lyα) ≲ 42.5 after correction for magnification. This sample is particularly sensitive to the slope of the luminosity function toward the faintest end. The density of sources obtained in this survey is consistent with a steep value of α ≤ -1.5, although this result still

  6. The distribution of dark and luminous matter in the unique galaxy cluster merger Abell 2146

    NASA Astrophysics Data System (ADS)

    King, Lindsay J.; Clowe, Douglas I.; Coleman, Joseph E.; Russell, Helen R.; Santana, Rebecca; White, Jacob A.; Canning, Rebecca E. A.; Deering, Nicole J.; Fabian, Andrew C.; Lee, Brandyn E.; Li, Baojiu; McNamara, Brian R.

    2016-06-01

    Abell 2146 (z = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the Chandra X-ray Observatory, consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the total gravitating mass in the system, using the distorted shapes of distant galaxies seen with Advanced Camera for Surveys - Wide Field Channel on Hubble Space Telescope, is presented. The highest peak in the reconstruction of the projected mass is centred on the brightest cluster galaxy (BCG) in Abell 2146-A. The mass associated with Abell 2146-B is more extended. Bootstrapped noise mass reconstructions show the mass peak in Abell 2146-A to be consistently centred on the BCG. Previous work showed that BCG-A appears to lag behind an X-ray cool core; although the peak of the mass reconstruction is centred on the BCG, it is also consistent with the X-ray peak given the resolution of the weak lensing mass map. The best-fitting mass model with two components centred on the BCGs yields M200 = 1.1^{+0.3}_{-0.4} × 1015 and 3^{+1}_{-2} × 1014 M⊙ for Abell 2146-A and Abell 2146-B, respectively, assuming a mass concentration parameter of c = 3.5 for each cluster. From the weak lensing analysis, Abell 2146-A is the primary halo component, and the origin of the apparent discrepancy with the X-ray analysis where Abell 2146-B is the primary halo is being assessed using simulations of the merger.

  7. The X-ray luminosity functions of Abell clusters from the Einstein Cluster Survey

    NASA Technical Reports Server (NTRS)

    Burg, R.; Giacconi, R.; Forman, W.; Jones, C.

    1994-01-01

    We have derived the present epoch X-ray luminosity function of northern Abell clusters using luminosities from the Einstein Cluster Survey. The sample is sufficiently large that we can determine the luminosity function for each richness class separately with sufficient precision to study and compare the different luminosity functions. We find that, within each richness class, the range of X-ray luminosity is quite large and spans nearly a factor of 25. Characterizing the luminosity function for each richness class with a Schechter function, we find that the characteristic X-ray luminosity, L(sub *), scales with richness class as (L(sub *) varies as N(sub*)(exp gamma), where N(sub *) is the corrected, mean number of galaxies in a richness class, and the best-fitting exponent is gamma = 1.3 +/- 0.4. Finally, our analysis suggests that there is a lower limit to the X-ray luminosity of clusters which is determined by the integrated emission of the cluster member galaxies, and this also scales with richness class. The present sample forms a baseline for testing cosmological evolution of Abell-like clusters when an appropriate high-redshift cluster sample becomes available.

  8. New machine-readable version of Abell catalog of clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Kalinkov, M.; Stavrev, K. Y.; Kuneva, I. F.

    An improved version of the magnetic-tape catalog of Abell and Zwicky clusters of galaxies (Kalinkov et al., 1976) is briefly characterized, with an emphasis on the distance-calibration and homogenization techniques employed in its compilation. The distance calibration is improved by performing regression analyses on clusters of known Bautz-Morgan type; parameter and standard-deviation values are presented in a table. Selection effects are investigated, and it is shown that the increase in absolute magnitude estimates with distance is less pronounced for the values based on the photored magnitude of the first-rank galaxy (Leir and van den Bergh, 1977) than for those determined by Abell (1958).

  9. Galaxy Luminosity Function of the Dynamically Young Abell 119 Cluster: Probing the Cluster Assembly

    NASA Astrophysics Data System (ADS)

    Lee, Youngdae; Rey, Soo-Chang; Hilker, Michael; Sheen, Yun-Kyeong; Yi, Sukyoung K.

    2016-05-01

    We present the galaxy luminosity function (LF) of the Abell 119 cluster down to {M}r˜ -14 mag based on deep images in the u, g, and r bands taken by using MOSAIC II CCD mounted on the Blanco 4 m telescope at the CTIO. The cluster membership was accurately determined based on the radial velocity information and on the color-magnitude relation for bright galaxies and the scaling relation for faint galaxies. The overall LF exhibits a bimodal behavior with a distinct dip at r˜ 18.5 mag ({M}r˜ -17.8 mag), which is more appropriately described by a two-component function. The shape of the LF strongly depends on the clustercentric distance and on the local galaxy density. The LF of galaxies in the outer, low-density region exhibits a steeper slope and more prominent dip compared with that of counterparts in the inner, high-density region. We found evidence for a substructure in the projected galaxy distribution in which several overdense regions in the Abell 119 cluster appear to be closely associated with the surrounding, possible filamentary structure. The combined LF of the overdense regions exhibits a two-component function with a distinct dip, while the LF of the central region is well described by a single Schechter function. We suggest that, in the context of the hierarchical cluster formation scenario, the observed overdense regions are the relics of galaxy groups, retaining their two-component LFs with a dip, which acquired their shapes through a galaxy merging process in group environments, before they fall into a cluster.

  10. The mass distribution of the unusual merging cluster Abell 2146 from strong lensing

    NASA Astrophysics Data System (ADS)

    Coleman, Joseph E.; King, Lindsay J.; Oguri, Masamune; Russell, Helen R.; Canning, Rebecca E. A.; Leonard, Adrienne; Santana, Rebecca; White, Jacob A.; Baum, Stefi A.; Clowe, Douglas I.; Edge, Alastair; Fabian, Andrew C.; McNamara, Brian R.; O'Dea, Christopher P.

    2017-01-01

    Abell 2146 consists of two galaxy clusters that have recently collided close to the plane of the sky, and it is unique in showing two large shocks on Chandra X-ray Observatory images. With an early stage merger, shortly after first core passage, one would expect the cluster galaxies and the dark matter to be leading the X-ray emitting plasma. In this regard, the cluster Abell 2146-A is very unusual in that the X-ray cool core appears to lead, rather than lag, the brightest cluster galaxy (BCG) in their trajectories. Here we present a strong-lensing analysis of multiple-image systems identified on Hubble Space Telescope images. In particular, we focus on the distribution of mass in Abell 2146-A in order to determine the centroid of the dark matter halo. We use object colours and morphologies to identify multiple-image systems; very conservatively, four of these systems are used as constraints on a lens mass model. We find that the centroid of the dark matter halo, constrained using the strongly lensed features, is coincident with the BCG, with an offset of ≈2 kpc between the centres of the dark matter halo and the BCG. Thus from the strong-lensing model, the X-ray cool core also leads the centroid of the dark matter in Abell 2146-A, with an offset of ≈30 kpc.

  11. Search for post-starburst (E+A) galaxies in the cluster Abell 3266

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongyu

    The objective of this work is to use spectroscopic techniques to further the understanding of the dynamical state of the galaxy cluster Abell 3266. This is a very rich cluster in the southern skies that has been extensively studied by many groups. The cluster shows evidence of a merger of substructure in its midst, but the geometry, dynamics, and age of this merger remain uncertain. Low resolution, fiber spectra of galaxies in Abell 3266 were analyzed and searched for “E+A” (post-starburst) galaxies, from which we selected two candidate “E+A” galaxies for follow-up high-resolution spectroscopy. The 2 candidate galaxies are confirmed as “E+A” galaxies with high-resolution, slit spectra. The ages of these “E+A” galaxies (i.e. time since their starburst occurred) are determined with the method developed by Leonardi & Rose (1996). We find that both galaxies had a major starburst in the past, but they occurred at significantly different epochs. If the starbursts are related to the recent merger history of Abell 3266, instead of being just isolated events, they would indicate that there may have been more than one merger in this cluster in the past 3 Gyr or so. This might explain the rather disparate conclusions that have been obtained in the past about the merger history of this cluster. To compare with other nearby clusters, “E+A” galaxies were also searched for among nearly 2400 galaxies in 26 clusters fields. Only 4 candidates are found. This result is consistent with the general observational fact that there are substantially fewer spectroscopically disturbed galaxies in nearby clusters than in distant clusters. The result is also in quantitative agreement with the findings in the larger, more homogeneous Las Campanas Redshift Survey, confirming the reliability of our identification in Abell 3266. The impact of these statistical analyses on the understanding of galaxy evolution in cluster environment is also discussed.

  12. Mass Distrubtion from Strong Gravitational Lensing of Merging Cluster Abell 2146

    NASA Astrophysics Data System (ADS)

    Coleman, Joseph E.; King, Lindsay J.; Oguri, Masamune; Russell, Helen

    2017-01-01

    The merging cluster Abell 2146 consists of two galaxy clusters that have recently collided close to the plane of the sky. In images from Chandra X-ray Observatory there are two distinct shock fronts in the intracluster medium. An unusual feature of one of the clusters is that the peak in the X-ray is leading the brightest cluster galaxy. The dark matter component is coincident with the brightest cluster galaxy (BCG). Shortly after first core passage one would typically expect the dark matter and BCG to lead the X-ray emitting plasma, however, that is not the case with Abell 2146. Strong lensing features were identified on images taken by the Hubble Space Telescope. These features were used as constraints on a lens model that maps the matter distribution of the system. We focus on the cluster Abell 2146-A to determine the dark matter centroid near BCG-A and the peak in the X-ray. The results from the strong lensing model indicate the X-ray cool core leads both the dark matter centroid and BCG-A. The dark matter centroid and BCG-A are separated by ≈ 2 kpc. The X-ray peak and dark matter centroid are separated by ≈ 30 kpc.

  13. Abell 2069 - An X-ray cluster of galaxies with multiple subcondensations

    NASA Technical Reports Server (NTRS)

    Gioia, I. M.; Maccacaro, T.; Geller, M. J.; Huchra, J. P.; Stocke, J.; Steiner, J. E.

    1982-01-01

    X-ray and optical observations of the cluster Abell 2069 are presented. The cluster is at a mean redshift of 0.116. The cluster shows multiple condensations in both the X-ray emission and in the galaxy surface density and, thus, does not appear to be relaxed. There is a close correspondence between the gas and galaxy distributions which indicates that the galaxies in this system do map the mass distribution, contrary to what might be expected if low-mass neutrinos dominate the cluster mass.

  14. A Study of Dwarf Galaxies in Five Rich Clusters I: Abell 1689 and Abell 1703

    NASA Astrophysics Data System (ADS)

    Bruursema, Justice; Riley, S.; Ford, H. C.; Zekser, K. C.; Infante, L.; Postman, M.

    2008-05-01

    Dwarf galaxies play an important role in understanding galactic formation, cluster dynamics, and large scale structure. Although local dwarf populations have been well studied, dwarf galaxies outside the local supercluster remain relatively unexamined. Using ACS Investigation Definition Team data, we examine the dwarf galaxy populations of A1689 (z=0.1832), A1703 (z=0.2580), A2218 (z=0.1756), CL0024+16 (z=0.395), and MS1358+62 (z=0.328). We have modeled and subtracted the light from the brighter elliptical galaxies using the XVISTA subroutine SNUC. An assumption of concentric elliptical isophotes is made and the position angle, ellipticity, and brightness are fit using a nonlinear least-squares algorithm. The subtraction of the models reveals a population of dwarf galaxies usually hidden by the light of bright ellipticals. SExtractor and Bayesian Photometric Redshifts (BPZ) are used in order to identify cluster members. With the 0.05" per pixel resolution of ACS and a completeness of mF625 = 28 we are able to identify approximately 1000 dwarf galaxies candidates, defined as MF625 > -18, in all five clusters combined. We will discuss the results of this research including, but not limited to, dwarf galaxy luminosity functions, radial distribution, and the characteristics of dwarfs compared to those in other well studied clusters. ACS was developed under NASA contract NAS5-32865, and this research was supported by NASA grant NAG5-7697.

  15. Detection of large-scale alignment of Lick counts around Abell clusters

    NASA Technical Reports Server (NTRS)

    Argyres, P. C.; Groth, E. J.; Peebles, P. J. E.; Struble, M. F.

    1986-01-01

    The possible tendency of galaxies to be distributed in an aligned fashion, on sheets or filaments, on scales greater than the Abell radius, has been tested by a variety of statistics. The subject remains controversial because the statistical tests have either not been sensitive to the alignment or capable of unambiguously signalling alignment in a general, clumpy distribution of galaxies. The present approach combines ideas of Bingelli (1982) and Fry and Peebles (1980) in an examination of the cross correlation of Lick counts relative to the preferred direction defined by the cluster. This can substantially reduce the noise, and it is suggested on this basis that alignment has been found on large scales for Lick galaxy counts and Abell cluster positions and their angles.

  16. The extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744

    NASA Astrophysics Data System (ADS)

    Jauzac, M.; Eckert, D.; Schwinn, J.; Harvey, D.; Baugh, C. M.; Robertson, A.; Bose, S.; Massey, R.; Owers, M.; Ebeling, H.; Shan, H. Y.; Jullo, E.; Kneib, J.-P.; Richard, J.; Atek, H.; Clément, B.; Egami, E.; Israel, H.; Knowles, K.; Limousin, M.; Natarajan, P.; Rexroth, M.; Taylor, P.; Tchernin, C.

    2016-12-01

    We present a joint optical/X-ray analysis of the massive galaxy cluster Abell 2744 (z = 0.308). Our strong- and weak-lensing analysis within the central region of the cluster, i.e. at R < 1 Mpc from the brightest cluster galaxy, reveals eight substructures, including the main core. All of these dark matter haloes are detected with a significance of at least 5σ and feature masses ranging from 0.5 to 1.4 × 1014 M⊙ within R < 150 kpc. Merten et al. and Medezinski et al. substructures are also detected by us. We measure a slightly higher mass for the main core component than reported previously and attribute the discrepancy to the inclusion of our tightly constrained strong-lensing mass model built on Hubble Frontier Fields data. X-ray data obtained by XMM-Newton reveal four remnant cores, one of them a new detection, and three shocks. Unlike Merten et al., we find all cores to have both dark and luminous counterparts. A comparison with clusters of similar mass in the Millennium XXL simulations yields no objects with as many massive substructures as observed in Abell 2744, confirming that Abell 2744 is an extreme system. We stress that these properties still do not constitute a challenge to Λ cold dark matter, as caveats apply to both the simulation and the observations: for instance, the projected mass measurements from gravitational lensing and the limited resolution of the subhaloes finders. We discuss implications of Abell 2744 for the plausibility of different dark matter candidates and, finally, measure a new upper limit on the self-interaction cross-section of dark matter of σDM < 1.28 cm2 g-1 (68 per cent CL), in good agreement with previous results from Harvey et al.

  17. Spectroscopic observations of the distant cluster of galaxies Abell 370 - A catalogue of 84 spectra

    NASA Astrophysics Data System (ADS)

    Soucail, G.; Mellier, Y.; Fort, B.; Cailloux, M.

    1988-06-01

    Spectroscopic and photometric data are presented on 84 objects in the field of the distant cluster of galaxies Abell 370 (z = 0.374) obtained with the multiaperture spectroscopic systems PUMA developed at the Toulouse Observatory for the CFHT and ESO. The redshift and the spectral types as well as CCD photometry in the B and R bands are given with a discussion on the accuracy of the different data and measurements.

  18. Constraining the Mass of the Spectacular Pandora's Cluster, Abell 2744

    NASA Astrophysics Data System (ADS)

    Carrasco, Rodrigo; Frye, Brenda; Coe, Dan; Dupke, Renato; Merten, Julian; Sodre, Laerte; Massey, Richard; Braglia, Filberto; Cypriano, Eduardo; Zitrin, Adi; Krick, Jessica; Benitez, Narciso

    2011-08-01

    Violent cluster mergers provide a unique opportunity to study the interplay between dark matter (DM) and ICM and to set constraints on the nature of DM. In particular, cluster mergers near first core passage allow us to ``see'' DM by comparing the spatial distribution of the intra-cluster gas (baryonic) to that of DM. We have recently finished a lensing analysis of the particularly interesting merging system, A2744, the Pandora cluster. We found that it is the result of a spectacular merging event, significantly more complex than the "Bullet Cluster", that produced a wide variety of new phenomenologies, among them, a Bullet, a Dark sub-cluster (no gas), a Ghost sub-cluster (no DM), which can provide fundamental insights to the physics of the ICM, and begs further observations. Our analyses revealed 34 arcs produced by strong gravitational lensing, none of which had been published to date. Spectroscopic redshifts of these arcs are essential to determine precise masses of the main merging system providing crucial information for further numerical simulations and to set stronger constraints on the DM self-interaction cross-section. Therefore we are requesting 17.2 hours on Gemini+GMOS-S, primarily to obtain spectroscopic redshifts of multiply strongly lensed arcs produced by this impressive cluster.

  19. Redshift observations of Abell/ACO galaxy clusters in two candidate superclusters

    NASA Astrophysics Data System (ADS)

    Batuski, D. J.; Maurogordato, S.; Balkowski, C.; Olowin, R. P.

    1995-02-01

    The results of spectroscopic observations of five R greater than or equal to 1 clusters of galaxies from the Abell (1958) and Abell et al. (1989) (hereafter ACO) catalogs are presented. The observations were conducted at the ESO 3.6m telescope with the EFOSC spectrograph and PUMA hole-punch aperture plates. Two of the clusters (A2576 and A2628) had been identified as members of one candidate supercluster that appears particularly dense in projection, and the other three clusters (A3802, A3817, and A3834) were in another candidate supercluster, based on redshifts estimated from the magnitudes of tenth brightest galaxies. Our observations confirm very similar redshifts for A2576 and A2628 ( z = 0.1875 and z = 0.1858, respectively) and for A3802 and A3834 (z = 0.1579 and z = 0.1518). From the agreement in redshifts and the proximity on the sky, it is suggestive that both pairs are indeed components of superclusters, although redshifts of other nearby candidates must be measured to determine the significance of the structure present. The fifth cluster, A3817, has a mean redshift of z = 0.2115, and so appears to be background to any possible A3802/A3834 supercluster. We note that the complex of clusters around A2576 and A2628 is a region of high spatial density, even ignoring the many clusters with unmeasured redshift. The region is an exceptional opportunity for large-scale structure study.

  20. Temperature and elemental abundances in the Abell cluster A 576 derived from X-ray observations

    NASA Technical Reports Server (NTRS)

    Rothenflug, R.; Vigroux, L.; Mushotzky, R. F.; Holt, S. S.

    1983-01-01

    Results of Einstein solid state spectrometer observations of the central region of Abell 576 combined with HEAO 1 spectra of the total cluster are given. Line emission was detected due to Fe, Si, and S from a hot plasma in the central region. The temperature of the total cluster spectrum may be in conflict with the central temperature. This difference can be explained either if cooling takes place in the center, or if part of the measured emission is due to individual galaxies. If the X-ray emission comes from the intergalactic gas only, there is some difficulty in producing all the silicon observed in the galaxies of A 576.

  1. The merging cluster Abell 1758 revisited: multi-wavelength observations and numerical simulations

    NASA Astrophysics Data System (ADS)

    Durret, F.; Laganá, T. F.; Haider, M.

    2011-05-01

    Context. Cluster properties can be more distinctly studied in pairs of clusters, where we expect the effects of interactions to be strong. Aims: We here discuss the properties of the double cluster Abell 1758 at a redshift z ~ 0.279. These clusters show strong evidence for merging. Methods: We analyse the optical properties of the North and South cluster of Abell 1758 based on deep imaging obtained with the Canada-France-Hawaii Telescope (CFHT) archive Megaprime/Megacam camera in the g' and r' bands, covering a total region of about 1.05 × 1.16 deg2, or 16.1 × 17.6 Mpc2. Our X-ray analysis is based on archive XMM-Newton images. Numerical simulations were performed using an N-body algorithm to treat the dark-matter component, a semi-analytical galaxy-formation model for the evolution of the galaxies and a grid-based hydrodynamic code with a parts per million (PPM) scheme for the dynamics of the intra-cluster medium. We computed galaxy luminosity functions (GLFs) and 2D temperature and metallicity maps of the X-ray gas, which we then compared to the results of our numerical simulations. Results: The GLFs of Abell 1758 North are well fit by Schechter functions in the g' and r' bands, but with a small excess of bright galaxies, particularly in the r' band; their faint-end slopes are similar in both bands. In contrast, the GLFs of Abell 1758 South are not well fit by Schechter functions: excesses of bright galaxies are seen in both bands; the faint-end of the GLF is not very well defined in g'. The GLF computed from our numerical simulations assuming a halo mass-luminosity relation agrees with those derived from the observations. From the X-ray analysis, the most striking features are structures in the metal distribution. We found two elongated regions of high metallicity in Abell 1758 North with two peaks towards the centre. In contrast, Abell 1758 South shows a deficit of metals in its central regions. Comparing observational results to those derived from numerical

  2. Tracing low-mass galaxy clusters using radio relics: the discovery of Abell 3527-bis

    NASA Astrophysics Data System (ADS)

    de Gasperin, F.; Intema, H. T.; Ridl, J.; Salvato, M.; van Weeren, R.; Bonafede, A.; Greiner, J.; Cassano, R.; Brüggen, M.

    2017-01-01

    Context. Galaxy clusters undergo mergers that can generate extended radio sources called radio relics. Radio relics are the consequence of merger-induced shocks that propagate in the intra cluster medium (ICM). Aims: In this paper we analyse the radio, optical and X-ray data from a candidate galaxy cluster that has been selected from the radio emission coming from a candidate radio relic detected in NRAO VLA Sky Survey (NVSS). Our aim is to clarify the nature of this source and prove that under certain conditions radio emission from radio relics can be used to trace relatively low-mass galaxy clusters. Methods: We observed the candidate galaxy cluster with the Giant Meterwave Radio Telescope (GMRT) at three different frequencies. These datasets have been analysed together with archival data from ROSAT in the X-ray and with archival data from the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) telescope in four different optical bands. Results: We confirm the presence of a 1 Mpc long radio relic located in the outskirts of a previously unknown galaxy cluster. We confirm the presence of the galaxy cluster through dedicated optical observations and using archival X-ray data. Due to its proximity and similar redshift to a known Abell cluster, we named it Abell 3527-bis. The galaxy cluster is amongst the least massive clusters known to host a radio relic. Conclusions: We showed that radio relics can be effectively used to trace a subset of relatively low-mass galaxy clusters that might have gone undetected in X-ray or Sunyaev-Zel'dovich (SZ) surveys. This technique might be used in future deep, low-frequency surveys such as those carried on by the Low Frequency Array (LOFAR), the Upgraded GMRT (uGMRT) and, ultimately, the Square Kilometre Array (SKA).

  3. See Change: the Supernova Sample from the Supernova Cosmology Project High Redshift Cluster Supernova Survey

    NASA Astrophysics Data System (ADS)

    Hayden, Brian; Perlmutter, Saul; Boone, Kyle; Nordin, Jakob; Rubin, David; Lidman, Chris; Deustua, Susana E.; Fruchter, Andrew S.; Aldering, Greg Scott; Brodwin, Mark; Cunha, Carlos E.; Eisenhardt, Peter R.; Gonzalez, Anthony H.; Jee, James; Hildebrandt, Hendrik; Hoekstra, Henk; Santos, Joana; Stanford, S. Adam; Stern, Daniel; Fassbender, Rene; Richard, Johan; Rosati, Piero; Wechsler, Risa H.; Muzzin, Adam; Willis, Jon; Boehringer, Hans; Gladders, Michael; Goobar, Ariel; Amanullah, Rahman; Hook, Isobel; Huterer, Dragan; Huang, Xiaosheng; Kim, Alex G.; Kowalski, Marek; Linder, Eric; Pain, Reynald; Saunders, Clare; Suzuki, Nao; Barbary, Kyle H.; Rykoff, Eli S.; Meyers, Joshua; Spadafora, Anthony L.; Sofiatti, Caroline; Wilson, Gillian; Rozo, Eduardo; Hilton, Matt; Ruiz-Lapuente, Pilar; Luther, Kyle; Yen, Mike; Fagrelius, Parker; Dixon, Samantha; Williams, Steven

    2017-01-01

    The Supernova Cosmology Project has finished executing a large (174 orbits, cycles 22-23) Hubble Space Telescope program, which has measured ~30 type Ia Supernovae above z~1 in the highest-redshift, most massive galaxy clusters known to date. Our SN Ia sample closely matches our pre-survey predictions; this sample will improve the constraint by a factor of 3 on the Dark Energy equation of state above z~1, allowing an unprecedented probe of Dark Energy time variation. When combined with the improved cluster mass calibration from gravitational lensing provided by the deep WFC3-IR observations of the clusters, See Change will triple the Dark Energy Task Force Figure of Merit. With the primary observing campaign completed, we present the preliminary supernova sample and our path forward to the supernova cosmology results. We also compare the number of SNe Ia discovered in each cluster with our pre-survey expectations based on cluster mass and SFR estimates. Our extensive HST and ground-based campaign has already produced unique results; we have confirmed several of the highest redshift cluster members known to date, confirmed the redshift of one of the most massive galaxy clusters at z~1.2 expected across the entire sky, and characterized one of the most extreme starburst environments yet known in a z~1.7 cluster. We have also discovered a lensed SN Ia at z=2.22 magnified by a factor of ~2.7, which is the highest spectroscopic redshift SN Ia currently known.

  4. Star formation in the massive cluster merger Abell 2744

    NASA Astrophysics Data System (ADS)

    Rawle, T. D.; Altieri, B.; Egami, E.; Pérez-González, P. G.; Richard, J.; Santos, J. S.; Valtchanov, I.; Walth, G.; Bouy, H.; Haines, C. P.; Okabe, N.

    2014-07-01

    We present a comprehensive study of star-forming (SF) galaxies in the Hubble Space Telescope (HST) Frontier Field recent cluster merger A2744 (z = 0.308). Wide-field, ultraviolet-infrared (UV-IR) imaging enables a direct constraint of the total star formation rate (SFR) for 53 cluster galaxies, with SFRUV+IR = 343 ± 10 M⊙ yr-1. Within the central 4 arcmin (1.1 Mpc) radius, the integrated SFR is complete, yielding a total SFRUV+IR = 201 ± 9 M⊙ yr-1. Focusing on obscured star formation, this core region exhibits a total SFRIR = 138 ± 8 M⊙ yr-1, a mass-normalized SFRIR of ΣSFR = 11.2 ± 0.7 M⊙ yr-1 per 1014 M⊙ and a fraction of IR-detected SF galaxies f_SF = 0.080^{+0.010}_{-0.037}. Overall, the cluster population at z ˜ 0.3 exhibits significant intrinsic scatter in IR properties (total SFRIR, Tdust distribution) apparently unrelated to the dynamical state: A2744 is noticeably different to the merging Bullet cluster, but similar to several relaxed clusters. However, in A2744 we identify a trail of SF sources including jellyfish galaxies with substantial unobscured SF due to extreme stripping (SFRUV/SFRIR up to 3.3). The orientation of the trail, and of material stripped from constituent galaxies, indicates that the passing shock front of the cluster merger was the trigger. Constraints on star formation from both IR and UV are crucial for understanding galaxy evolution within the densest environments.

  5. Narrow-angle tail radio sources and evidence for radial orbits in Abell clusters

    NASA Technical Reports Server (NTRS)

    O'Dea, Christopher P.; Owen, Frazer N.; Sarazin, Craig L.

    1986-01-01

    Published observational data on the tail orientations (TOs) of 60 narrow-angle-tail (NAT) radio sources in Abell clusters of galaxies are analyzed statistically using a maximum-likelihood approach. The results are presented in a table, and it is found that the observed TO distributions in the whole sample and in subsamples of morphologically regular NATs and NATs with pericentric distances d greater than 500 kpc are consistent with isotropic orbits, whereas the TOs for NATs with d less than 500 kpc are consistent with highly radial orbits. If radial orbits were observed near the centers of other types of cluster galaxies as well, it could be inferred that violent relaxation during cluster formation was incomplete, and that clusters form by spherical collapse and secondary infall, as proposed by Gunn (1977).

  6. Embedded Spiral Patterns in the Cool Core of the Massive Cluster of Galaxies Abell 1835

    NASA Astrophysics Data System (ADS)

    Ueda, Shutaro; Kitayama, Tetsu; Dotani, Tadayasu

    2017-03-01

    We present the properties of an intracluster medium (ICM) in the cool core of the massive cluster of galaxies, Abell 1835, obtained with the data from the Chandra X-ray Observatory. We find distinctive spiral patterns with a radius of 70 kpc (or 18″) as a whole in the residual image of the X-ray surface brightness after the two-dimensional ellipse model of surface brightness is subtracted. The size is smaller by a factor of 2–4 than that of other clusters that are known to have a similar pattern. The spiral patterns consist of two arms. One of them appears as positive, and the other appears as negative excesses in the residual image. Their X-ray spectra show that the ICM temperatures in the positive- and negative-excess regions are {5.09}-0.13+0.12 keV and {6.52}-0.15+0.18 keV, respectively. In contrast, no significant difference is found in the abundance or pressure, the latter of which suggests that the ICM in the two regions of the spiral patterns is near or is in pressure equilibrium. The spatially resolved X-ray spectroscopy of the central region (r< 40\\prime\\prime ), divided into 92 sub-regions indicates that Abell 1835 is a typical cool core cluster. We also find that the spiral patterns extend from the cool core out to the hotter surrounding ICM. The residual image reveals some lumpy substructures in the cool core. The line of sight component of the disturbance velocity that is responsible for the substructures is estimated to be lower than 600 km s‑1. Abell 1835 may now be experiencing an off-axis minor merger.

  7. Enhanced momentum feedback from clustered supernovae

    NASA Astrophysics Data System (ADS)

    Gentry, Eric S.; Krumholz, Mark R.; Dekel, Avishai; Madau, Piero

    2017-02-01

    Young stars typically form in star clusters, so the supernovae (SNe) they produce are clustered in space and time. This clustering of SNe may alter the momentum per SN deposited in the interstellar medium (ISM) by affecting the local ISM density, which in turn affects the cooling rate. We study the effect of multiple SNe using idealized 1D hydrodynamic simulations which explore a large parameter space of the number of SNe, and the background gas density and metallicity. The results are provided as a table and an analytic fitting formula. We find that for clusters with up to ∼100 SNe, the asymptotic momentum scales superlinearly with the number of SNe, resulting in a momentum per SN which can be an order of magnitude larger than for a single SN, with a maximum efficiency for clusters with 10-100 SNe. We argue that additional physical processes not included in our simulations - self-gravity, breakout from a galactic disc, and galactic shear - can slightly reduce the momentum enhancement from clustering, but the average momentum per SN still remains a factor of 4 larger than the isolated SN value when averaged over a realistic cluster mass function for a star-forming galaxy. We conclude with a discussion of the possible role of mixing between hot and cold gas, induced by multidimensional instabilities or pre-existing density variations, as a limiting factor in the build-up of momentum by clustered SNe, and suggest future numerical experiments to explore these effects.

  8. On the merging cluster Abell 578 and its central radio galaxy 4C+67.13

    DOE PAGES

    Hagino, K.; Stawarz, Ł.; Siemiginowska, A.; ...

    2015-05-26

    Here we analyze radio, optical, and X-ray data for the peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy (BCG), CGPG 0719.8+6704, is a pair of interacting ellipticals with projected separation ~10 kpc, the brighter of which hosts the radio source 4C+67.13. The Fanaroff–Riley type-II radio morphology of 4C+67.13 is unusual for central radio galaxies in local Abell clusters. Our new optical spectroscopy revealed that both nuclei of the CGPG 0719.8+6704 pair are active, albeit at low accretion rates corresponding to the Eddington ratiomore » $$\\sim {{10}^{-4}}$$ (for the estimated black hole masses of $$\\sim 3\\times {{10}^{8}}\\;{{M}_{\\odot }}$$ and $$\\sim {{10}^{9}}\\;{{M}_{\\odot }}$$). The gathered X-ray (Chandra) data allowed us to confirm and to quantify robustly the previously noted elongation of the gaseous atmosphere in the dominant sub-cluster, as well as a large spatial offset (~60 kpc projected) between the position of the BCG and the cluster center inferred from the modeling of the X-ray surface brightness distribution. Detailed analysis of the brightness profiles and temperature revealed also that the cluster gas in the vicinity of 4C+67.13 is compressed (by a factor of about ~1.4) and heated (from $$\\simeq 2.0$$ keV up to 2.7 keV), consistent with the presence of a weak shock (Mach number ~1.3) driven by the expanding jet cocoon. As a result, this would then require the jet kinetic power of the order of $$\\sim {{10}^{45}}$$ erg s–1, implying either a very high efficiency of the jet production for the current accretion rate, or a highly modulated jet/accretion activity in the system.« less

  9. On the merging cluster Abell 578 and its central radio galaxy 4C+67.13

    SciTech Connect

    Hagino, K.; Stawarz, Ł.; Siemiginowska, A.; Cheung, C. C.; Kozieł-Wierzbowska, D.; Szostek, A.; Madejski, G.; Harris, D. E.; Simionescu, A.; Takahashi, T.

    2015-05-26

    Here we analyze radio, optical, and X-ray data for the peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy (BCG), CGPG 0719.8+6704, is a pair of interacting ellipticals with projected separation ~10 kpc, the brighter of which hosts the radio source 4C+67.13. The Fanaroff–Riley type-II radio morphology of 4C+67.13 is unusual for central radio galaxies in local Abell clusters. Our new optical spectroscopy revealed that both nuclei of the CGPG 0719.8+6704 pair are active, albeit at low accretion rates corresponding to the Eddington ratio $\\sim {{10}^{-4}}$ (for the estimated black hole masses of $\\sim 3\\times {{10}^{8}}\\;{{M}_{\\odot }}$ and $\\sim {{10}^{9}}\\;{{M}_{\\odot }}$). The gathered X-ray (Chandra) data allowed us to confirm and to quantify robustly the previously noted elongation of the gaseous atmosphere in the dominant sub-cluster, as well as a large spatial offset (~60 kpc projected) between the position of the BCG and the cluster center inferred from the modeling of the X-ray surface brightness distribution. Detailed analysis of the brightness profiles and temperature revealed also that the cluster gas in the vicinity of 4C+67.13 is compressed (by a factor of about ~1.4) and heated (from $\\simeq 2.0$ keV up to 2.7 keV), consistent with the presence of a weak shock (Mach number ~1.3) driven by the expanding jet cocoon. As a result, this would then require the jet kinetic power of the order of $\\sim {{10}^{45}}$ erg s–1, implying either a very high efficiency of the jet production for the current accretion rate, or a highly modulated jet/accretion activity in the system.

  10. The Distance and Mass of the Galaxy Cluster Abell 1995 Derived From Sunyaev-Zel'dovich Effect and X-Ray Measurements

    NASA Technical Reports Server (NTRS)

    Patel, Sandeep K.; Joy, Marshall; Carlstrom, John E.; Holder, Gilbert P.; Reese, Erik D.; Gomez, Percy L.; Hughes, John P.; Grego, Laura; Holzapfel, William L.

    2000-01-01

    We present multi-wavelength observations of the Abell 1995 galaxy cluster. From analysis of x-ray spectroscopy and imaging data we derive the electron temperature, cluster core radius, and central electron number density. Using optical spectroscopy of 15 cluster members, we derive an accurate cluster redshift and velocity dispersion. Finally, the interferometric imaging of the SZE toward Abell 1995 at 28.5 GHz provides a measure of the integrated pressure through the cluster.

  11. X-ray constraints on the shape of the dark matter in five Abell clusters

    NASA Technical Reports Server (NTRS)

    Buote, David A.; Canizares, Claude R.

    1992-01-01

    X-ray observations obtained with the Einstein Observatory are used to constrain the shape of the dark matter in the inner regions of Abell clusters A401, A426, A1656, A2029, and A2199, each of which exhibits highly flattened optical isopleths. The dark matter is modeled as an ellipsoid with a mass density of about r exp -2. The possible shapes of the dark matter is constrained by comparing these model isophotes to the image isophotes. The X-ray isophotes, and therefore the gravitational potentials, have ellipticities of about 0.1-0.2. The dark matter within the central 1 Mpc is found to be substantially rounder for all the clusters. It is concluded that the shape of the galaxy distributions in these clusters traces neither the gravitational potential nor the gravitating matter.

  12. ASCA detection of iron line emission from the distant galaxy cluster Abell 370

    NASA Technical Reports Server (NTRS)

    Bautz, Marshall W.; Mushotzky, Richard; Fabian, Andrew C.; Yamashita, Koujun; Gendreau, Keith C.; Arnaud, Keith A.; Crew, Geoffrey B.; Tawara, Yuzuru

    1994-01-01

    ASCA observations of the gravitational lens and Butcher-Oemler cluster Abell 370 (z = 0.37) give kT = 8.8 +/- 0.8 keV and A = 0.5 +/- 0.1 cosmic. If the gas were isothermal the implied cluster mass would be M(sub vir) = (1.5 +/- 0.4) x 10(exp 15) solar masses, a value consistent with the optically-determined virial mass. We detect iron K line emission with high confidence. This measurement increases, by a large factor, the lookback time at which the presence of iron in the intracluster medium has been established. The iron abundance is marginally higher than that of low-redshift clusters of similar temperature, so our results are consistent with models in which all enrichment occurs before the epoch corresponding to z = 0.37.

  13. A redshift survey of the strong-lensing cluster ABELL 383

    SciTech Connect

    Geller, Margaret J.; Hwang, Ho Seong; Kurtz, Michael J.; Diaferio, Antonaldo; Coe, Dan; Rines, Kenneth J. E-mail: hhwang@cfa.harvard.edu E-mail: diaferio@ph.unito.it E-mail: kenneth.rines@wwu.edu

    2014-03-01

    Abell 383 is a famous rich cluster (z = 0.1887) imaged extensively as a basis for intensive strong- and weak-lensing studies. Nonetheless, there are few spectroscopic observations. We enable dynamical analyses by measuring 2360 new redshifts for galaxies with r {sub Petro} ≤ 20.5 and within 50' of the Brightest Cluster Galaxy (BCG; R.A.{sub 2000} = 42.°014125, decl.{sub 2000} = –03.°529228). We apply the caustic technique to identify 275 cluster members within 7 h {sup –1} Mpc of the hierarchical cluster center. The BCG lies within –11 ± 110 km s{sup –1} and 21 ± 56 h {sup –1} kpc of the hierarchical cluster center; the velocity dispersion profile of the BCG appears to be an extension of the velocity dispersion profile based on cluster members. The distribution of cluster members on the sky corresponds impressively with the weak-lensing contours of Okabe et al. especially when the impact of foreground and background structure is included. The values of R {sub 200} = 1.22 ± 0.01 h {sup –1} Mpc and M {sub 200} = (5.07 ± 0.09) × 10{sup 14} h {sup –1} M {sub ☉} obtained by application of the caustic technique agree well with recent completely independent lensing measures. The caustic estimate extends direct measurement of the cluster mass profile to a radius of ∼5 h {sup –1} Mpc.

  14. Deep spectroscopy of nearby galaxy clusters - I. Spectroscopic luminosity function of Abell 85

    NASA Astrophysics Data System (ADS)

    Agulli, I.; Aguerri, J. A. L.; Sánchez-Janssen, R.; Dalla Vecchia, C.; Diaferio, A.; Barrena, R.; Dominguez Palmero, L.; Yu, H.

    2016-05-01

    We present a new deep spectroscopic catalogue for Abell 85, within 3.0 × 2.6 Mpc2 and down to Mr ˜ Mr^{ast } +6. Using the Visible Multi-Object Spectrograph at the Very Large Telescope and the AutoFiber 2 at the William Herschel Telescope, we obtained almost 1430 new redshifts for galaxies with mr ≤ 21 mag and <μe,r> ≤ 24 mag arcsec-2. These redshifts, together with Sloan Digital Sky Survey Data Release 6 and NASA/IPAC Extragaalctic Database spectroscopic information, result in 460 confirmed cluster members. This data set allows the study of the luminosity function (LF) of the cluster galaxies covering three orders of magnitudes in luminosities. The total and radial LFs are best modelled by a double Schechter function. The normalized LFs show that their bright (Mr ≤ -21.5) and faint (Mr ≥ -18.0) ends are independent of clustercentric distance and similar to the field LFs unlike the intermediate luminosity range (-21.5 ≤ Mr ≤ -18.0). Similar results are found for the LFs of the dominant types of galaxies: red, passive, virialized and early-infall members. On the contrary, the LFs of blue, star forming, non-virialized and recent-infall galaxies are well described by a single Schechter function. These populations contribute to a small fraction of the galaxy density in the innermost cluster region. However, in the outskirts of the cluster, they have similar densities to red, passive, virialized and early-infall members at the LF faint end. These results confirm a clear dependence of the colour and star formation of Abell 85 members in the cluster centric distance.

  15. Early-type Galaxies in the Cluster Abell 2390 at z = 0.23

    NASA Astrophysics Data System (ADS)

    Fritz, A.; Ziegler, B. L.; Bower, R. G.; Smail, I.; Davies, R. L.

    To examine the evolution of the early-type galaxy population in the rich cluster Abell 2390 at z = 0.23 we have gained spectroscopic data of 51 elliptical and lenticular galaxies with MOSCA at the 3.5 m telescope on Calar Alto Observatory. This investigation spans both a broad range in luminosity (-19.3 >˜MB >˜-22.3) and uses a wide field of view of 10'× 10', therefore the environmental dependence of different formation scenarios can be analysed in detail as a function of radius from the cluster centre. Here we present results on the surface brightness modelling of galaxies where morphological and structural information is available in the F814W filter aboard the Hubble Space Telescope (HST) and investigate for this subsample the evolution of the Fundamental Plane.

  16. A Cosmic Train Wreck: JVLA Radio Observations of the HST Frontier Fields Cluster Abell 2744

    NASA Astrophysics Data System (ADS)

    Pearce, Connor; Van Weeren, Reinout J.; Jones, Christine; Forman, William R.; Ogrean, Georgiana A.; Andrade-Santos, Felipe; Kraft, Ralph P.; Dawson, William; Brüggen, Marcus; Roediger, Elke; Bulbul, Esra; Mroczkowski, Tony

    2016-01-01

    The galaxy cluster mergers observed in the HST Frontier Fields represent some of the most energetic events in the Universe. Major cluster mergers leave distinct signatures in the ICM in the form of shocks, turbulence, and diffuse cluster radio sources. These diffuse radio sources, so-called radio relics and halos, provide evidence for the acceleration of relativistic particles and the presence of large scale magnetic fields in the ICM. Observations of these halos and relics allow us to (i) study the physics of particle acceleration and its relation with shocks and turbulence in the ICM and (ii) constrain the dynamical evolution of the merger eventsWe present Jansky Very Large Array 1-4 GHz observations of the Frontier cluster Abell 2744. We confirm the presence of the known giant radio halo and radio relic via our deep radio images. Owing to the much greater sensitivity of the JVLA compared to previous observations, we are able to detect a previously unobserved long Mpc-size filament of synchrotron emission to the south west of the cluster core. We also present a radio spectral index image of the diffuse cluster emission to test the origin of the radio relic and halo, related to the underlying particle acceleration mechanism. Finally, we carry out a search for radio emission from the 'jellyfish' galaxies in A2744 to estimate their star formation rate. These highly disturbed galaxies are likely influenced by the cluster merger event, although the precise origin of these galaxies is still being debated.

  17. X-Ray Spectroscopy of the Cluster of Galaxies Abell 1795 with XMM-Newton

    NASA Technical Reports Server (NTRS)

    Tamura, T.; Kaastra, J. S.; Peterson, J. R.; Paerels, F.; Mittaz, J. P. D.; Trudolyubov, S. P.; Stewart, G.; Fabian, A. C.; Mushotzky, R. F.; Lumb, D. H.

    2000-01-01

    The initial results from XMM-Newton observations of the rich cluster of galaxies Abell 1795 are presented. The spatially-resolved X-ray spectra taken by the European Photon Imaging Cameras (EPIC) show a temperature drop at a radius of - 200 kpc from the cluster center, indicating that the ICM is cooling. Both the EPIC and the Reflection Grating Spectrometers (RGS) spectra extracted from the cluster center can be described by an isothermal model with a temperature of approx. 4 keV. The volume emission measure of any cool component (less than 1 keV) is less than a few % of the hot component at the cluster center. A strong O VIII Lyman alpha line was detected with the RGS from the cluster core. The O abundance of the ICM is 0.2-0.5 times the solar value. The O to Fe ratio at the cluster center is 0.5 - 1.5 times the solar ratio.

  18. The Velocity Dispersion Function of Very Massive Galaxy Clusters: Abell 2029 and Coma

    NASA Astrophysics Data System (ADS)

    Sohn, Jubee; Geller, Margaret J.; Zahid, H. Jabran; Fabricant, Daniel G.; Diaferio, Antonaldo; Rines, Kenneth J.

    2017-04-01

    Based on an extensive redshift survey for galaxy clusters Abell 2029 and Coma, we measure the luminosity functions (LFs) and stellar mass functions (SMFs) for the entire cluster member galaxies. Most importantly, we measure the velocity dispersion functions (VDFs) for quiescent members. The MMT/Hectospec redshift survey for galaxies in A2029 identifies 982 spectroscopic members; for 838 members, we derive the central velocity dispersion from the spectroscopy. Coma is the only other cluster surveyed as densely. The LFs, SMFs, and VDFs for A2029 and Coma are essentially identical. The SMFs of the clusters are consistent with simulations. The A2029 and Coma VDFs for quiescent galaxies have a significantly steeper slope than those of field galaxies for velocity dispersion ≲ 100 {km} {{{s}}}-1. The cluster VDFs also exceed the field at velocity dispersion ≳ 250 {km} {{{s}}}-1. The differences between cluster and field VDFs are potentially important tests of simulations and of the formation of structure in the universe.

  19. HUBBLE CAPTURES VIEW OF SUPERNOVA BLAST IN REMOTE GALAXY CLUSTER

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In March 1996, the Hubble Space Telescope's Wide Field and Planetary Camera 2 just happened to be pointed at the faraway galaxy cluster MS1054-0321 when it captured the light from an exploding star, called supernova 1996CL. The cluster is 8 billion light-years from Earth. The Hubble telescope can clearly distinguish the supernova light from the glow of its parent galaxy. The larger image on the left shows the entire cluster of galaxies. The galaxy where the supernova was discovered is located in the boxed area. The bright knot of light from the supernova and the fainter glow from the parent galaxy are shown in the inset image on the right. The arrow points to the light from the supernova explosion. The supernova was discovered by members of the Supernova Cosmology Project, led by Saul Perlmutter of Lawrence Berkeley Laboratory in California. Perlmutter and his team made this discovery using images from the Hubble telescope and ground-based observatories. The Hubble data were furnished by Megan Donahue of the Space Telescope Science Institute. Donahue was using the Hubble telescope to study galaxy cluster MS1054-0321. Members of the Supernova Project use ground-based telescopes to search for distant supernovae, such as 1996CL, by comparing multiple, wide-field images of galaxies and clusters of galaxies taken at different times. Supernovae are named for the year and the order in which they are found. Supernova 1996CL is a Type Ia supernova. Exploding stars of this type are particularly useful for cosmology because they share a standard maximum brightness. By measuring this brightness, astronomers can determine a Type Ia's distance from Earth. Astronomers use this information to measure the expansion rate of the universe.

  20. The Merger in Abell 576: A Line-of-Sight Bullet Cluster?

    NASA Astrophysics Data System (ADS)

    Dupke, Renato A.; Mirabal, Nestor; Bregman, Joel N.; Evrard, August E.

    2007-10-01

    Using a combination of Chandra and XMM-Newton observations, we confirmed the presence of a significant velocity gradient along the northeast-southwest direction in the intracluster gas of the cluster Abell 576. The results are consistent with a previous ASCA SIS analysis of this cluster. The error-weighted average over the ACIS-S3 and EPIC MOS1 and MOS2 spectrometers for the maximum velocity difference is >3.3×103 km s-1 at the 90% confidence level, similar to the velocity limits estimated indirectly for the Bullet Cluster (1E 0657-56). The probability that the velocity gradient is generated by standard random gain fluctuations with Chandra and XMM-Newton is <0.1%. The regions of maximum velocity gradient are in CCD zones that have the lowest temporal gain variations. It is unlikely that the velocity gradient is due to Hubble distance differences between projected clusters (probability <~0.01%). We mapped the distribution of elemental abundance ratios across the cluster and detected a strong chemical discontinuity using the abundance ratio of silicon to iron, equivalent to a variation from 100% SN Ia iron mass fraction in the west-northwest regions to 32% in the eastern region. The ``center'' of the cluster is located at the chemical discontinuity boundary, which is inconsistent with the radially symmetric chemical gradient found in some regular clusters, but consistent with a cluster merging scenario. We predict that the velocity gradient as measured will produce a variation of the cosmic microwave background (CMB) temperature toward the east of the core of the cluster that will be detectable by current and near-future bolometers. The measured velocity gradient opens up the possibility that this cluster is passing through a near line-of-sight merger stage where the cores have recently crossed.

  1. Separating galaxies from the cluster dark matter halo in Abell 611

    NASA Astrophysics Data System (ADS)

    Monna, A.; Seitz, S.; Geller, M. J.; Zitrin, A.; Mercurio, A.; Suyu, S. H.; Postman, M.; Fabricant, D. G.; Hwang, H. S.; Koekemoer, A.

    2017-03-01

    We investigate the mass content of galaxies in the core of the galaxy cluster Abell 611. We perform a strong lensing analysis of the cluster core and use velocity dispersion measurements for individual cluster members as additional constraints. Despite the small number of multiply-imaged systems and cluster members with central velocity dispersions available in the core of A611, the addition of velocity dispersion measurements leads to tighter constraints on the mass associated with the galaxy component, and as a result, on the mass associated with the dark matter halo. Without the spectroscopic velocity dispersions, we would overestimate the mass of the galaxy component by a factor of ∼1.5, or, equivalently, we would underestimate the mass of the cluster dark halo by ∼5 per cent. We perform an additional lensing analysis using surface brightness (SB) reconstruction of the tangential giant arc. This approach improves the constraints on the mass parameters of the five galaxies close to the arc by a factor up to ∼10. The resulting parameters are in good agreement with the σ-rtr scaling relation derived in the pointlike analysis. The galaxy velocity dispersions resulting from the SB analysis are consistent at the 1σ confidence level with the spectroscopic measurements. In contrast, the truncation radii for 2-3 galaxies depart significantly from the galaxy scaling relation and suggest differences in the stripping history from galaxy to galaxy.

  2. On the Merging Cluster Abell 578 and Its Central Radio Galaxy 4C+67.13

    NASA Astrophysics Data System (ADS)

    Hagino, K.; Stawarz, Ł.; Siemiginowska, A.; Cheung, C. C.; Kozieł-Wierzbowska, D.; Szostek, A.; Madejski, G.; Harris, D. E.; Simionescu, A.; Takahashi, T.

    2015-06-01

    Here we analyze radio, optical, and X-ray data for the peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy (BCG), CGPG 0719.8+6704, is a pair of interacting ellipticals with projected separation ˜10 kpc, the brighter of which hosts the radio source 4C+67.13. The Fanaroff-Riley type-II radio morphology of 4C+67.13 is unusual for central radio galaxies in local Abell clusters. Our new optical spectroscopy revealed that both nuclei of the CGPG 0719.8+6704 pair are active, albeit at low accretion rates corresponding to the Eddington ratio ˜ {{10}-4} (for the estimated black hole masses of ˜ 3× {{10}8} {{M}⊙ } and ˜ {{10}9} {{M}⊙ }). The gathered X-ray (Chandra) data allowed us to confirm and to quantify robustly the previously noted elongation of the gaseous atmosphere in the dominant sub-cluster, as well as a large spatial offset (˜60 kpc projected) between the position of the BCG and the cluster center inferred from the modeling of the X-ray surface brightness distribution. Detailed analysis of the brightness profiles and temperature revealed also that the cluster gas in the vicinity of 4C+67.13 is compressed (by a factor of about ˜1.4) and heated (from ≃ 2.0 keV up to 2.7 keV), consistent with the presence of a weak shock (Mach number ˜1.3) driven by the expanding jet cocoon. This would then require the jet kinetic power of the order of ˜ {{10}45} erg s-1, implying either a very high efficiency of the jet production for the current accretion rate, or a highly modulated jet/accretion activity in the system. Based on service observations made with the WHT operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

  3. A Statistical Study of Multiply Imaged Systems in the Lensing Cluster Abell 68

    NASA Astrophysics Data System (ADS)

    Richard, Johan; Kneib, Jean-Paul; Jullo, Eric; Covone, Giovanni; Limousin, Marceau; Ellis, Richard; Stark, Daniel; Bundy, Kevin; Czoske, Oliver; Ebeling, Harald; Soucail, Geneviève

    2007-06-01

    We have carried out an extensive spectroscopic survey with the Keck and VLT telescopes, targeting lensed galaxies in the background of the massive cluster Abell 68. Spectroscopic measurements are obtained for 26 lensed images, including a distant galaxy at z=5.4. Redshifts have been determined for 5 out of 7 multiple-image systems. Through a careful modeling of the mass distribution in the strongly lensed regime, we derive a mass estimate of 5.3×1014 Msolar within 500 kpc. Our mass model is then used to constrain the redshift distribution of the remaining multiply imaged and singly imaged sources. This enables us to examine the physical properties for a subsample of 7 Lyα emitters at 1.7<~z<~5.5, whose unlensed luminosities of ~=1041 ergs s-1 are fainter than similar objects found in blank fields. Of particular interest is an extended Lyα emission region surrounding a highly magnified source at z=2.6, detected in VIMOS integral field spectroscopy data. The physical scale of the most distant lensed source at z=5.4 is very small (<300 pc), similar to the lensed z~5.6 emitter reported by Ellis et al. in Abell 2218. New photometric data available for Abell 2218 allow for a direct comparison between these two unique objects. Our survey illustrates the practicality of using lensing clusters to probe the faint end of the z~2-5 Lyα luminosity function in a manner that is complementary to blank-field narrowband surveys. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Also based on observations collected at the Very Large Telescope (Antu/UT1 and Melipal/UT3), European Southern Observatory, Paranal, Chile (ESO programs 070.A-0643 and 073.A-0774), the NASA/ESA Hubble Space Telescope

  4. RADIO AND DEEP CHANDRA OBSERVATIONS OF THE DISTURBED COOL CORE CLUSTER ABELL 133

    SciTech Connect

    Randall, S. W.; Nulsen, P. E. J.; Forman, W. R.; Murray, S. S.; Clarke, T. E.; Owers, M. S.; Sarazin, C. L.

    2010-10-10

    We present results based on new Chandra and multi-frequency radio observations of the disturbed cool core cluster Abell 133. The diffuse gas has a complex bird-like morphology, with a plume of emission extending from two symmetric wing-like features. The plume is capped with a filamentary radio structure that has been previously classified as a radio relic. X-ray spectral fits in the region of the relic indicate the presence of either high-temperature gas or non-thermal emission, although the measured photon index is flatter than would be expected if the non-thermal emission is from inverse Compton scattering of the cosmic microwave background by the radio-emitting particles. We find evidence for a weak elliptical X-ray surface brightness edge surrounding the core, which we show is consistent with a sloshing cold front. The plume is consistent with having formed due to uplift by a buoyantly rising radio bubble, now seen as the radio relic, and has properties consistent with buoyantly lifted plumes seen in other systems (e.g., M87). Alternatively, the plume may be a gas sloshing spiral viewed edge-on. Results from spectral analysis of the wing-like features are inconsistent with the previous suggestion that the wings formed due to the passage of a weak shock through the cool core. We instead conclude that the wings are due to X-ray cavities formed by displacement of X-ray gas by the radio relic. The central cD galaxy contains two small-scale cold gas clumps that are slightly offset from their optical and UV counterparts, suggestive of a galaxy-galaxy merger event. On larger scales, there is evidence for cluster substructure in both optical observations and the X-ray temperature map. We suggest that the Abell 133 cluster has recently undergone a merger event with an interloping subgroup, initialing gas sloshing in the core. The torus of sloshed gas is seen close to edge-on, leading to the somewhat ragged appearance of the elliptical surface brightness edge. We show

  5. Star formation quenching and stellar mass in the cluster Abell 85

    NASA Astrophysics Data System (ADS)

    Fadda, Dario; Habas, Rebecca; Marleau, Francine; Biviano, Andrea; Durret, Florence

    2017-01-01

    We report the discovery of a group of galaxies falling into the cluster Abell 85 showing a decrease in star formation limited to its dwarf galaxy population. We covered the cluster and its surroundings with a multi-wavelength survey from the UV to the far-IR using ground and space telescopes (including GALEX, Spitzer, and Herschel) and followed-up these observations with spectroscopic surveys with the WIYN/Hydra and VLT/VIMOS instruments. We were able to obtain spectra for 522 members down to r'=20, 30% of them showing H-alpha emission. We estimated the variation in star formation rate by using two different estimators based on continuum (UV) and line (H-alpha) emission. While massive infalling galaxies continue to produce stars during the infall, the star formation in dwarf galaxies appear to be quenched by the cluster environment. Considering the different time-scales of the two estimators, we can estimate that the quenching happens in a period of approximately 10 Myr.

  6. Systematic Uncertainties in Characterizing Cluster Outskirts: The Case of Abell 133

    NASA Astrophysics Data System (ADS)

    Paine, Jennie; Ogrean, Georgiana A.; Nulsen, Paul; Farrah, Duncan

    2016-01-01

    The outskirts of galaxy clusters have low surface brightness compared to the X-ray background, making accurate background subtraction particularly important for analyzing cluster spectra out to and beyond the virial radius. We analyze the thermodynamic properties of the intracluster medium (ICM) of Abell 133 and assess the extent to which uncertainties on background subtraction affect measured quantities. We implement two methods of analyzing the ICM spectra: one in which the blank-sky background is subtracted, and another in which the sky background is modeled. We find that the two methods are consistent within the 90% confidence ranges. We were able to measure the thermodynamic properties of the cluster up to R500. Even at R500, the systematic uncertainties associated with the sky background in the direction of A133 are small, despite the ICM signal constituting only ~25% of the total signal. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution. GAO acknowledges support by NASA through a Hubble Fellowship grant HST-HF2-51345.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

  7. Search for a non-equilibrium plasma in the merging galaxy cluster Abell 754

    NASA Astrophysics Data System (ADS)

    Inoue, Shota; Hayashida, Kiyoshi; Ueda, Shutaro; Nagino, Ryo; Tsunemi, Hiroshi; Koyama, Katsuji

    2016-06-01

    Abell 754 is a galaxy cluster in which an ongoing merger is evident on the plane of the sky, from the southeast to the northwest. We study the spatial variation of the X-ray spectra observed with Suzaku along the merging direction, centering on the Fe Ly α/Fe He α line ratio to search for possible deviation from ionization equilibrium. Fitting with a single-temperature collisional non-equilibrium plasma model shows that the electron temperature increases from the southeast to the northwest. The ionization parameter is consistent with that in equilibrium (net > 1013 s cm-3) except for the specific region with the highest temperature (kT=13.3_{-1.1}^{+1.4}keV) where n_et=10^{11.6_{-1.7}^{+0.6}}s cm-3. The elapsed time from the plasma heating estimated from the ionization parameter is 0.36-76 Myr at the 90% confidence level. This timescale is quite short but consistent with the traveling time of a shock to pass through that region. We thus interpret that the non-equilibrium ionization plasma in Abell 754 observed is a remnant of the shock heating in the merger process. However, we note that the X-ray spectrum of the specific region where the non-equilibrium is found can also be fitted with a collisional ionization plasma model with two temperatures, low kT=4.2^{+4.2}_{-1.5}keV and very high kT >19.3 keV. The very high temperature component is alternatively fitted with a power-law model. Either of these spectral models is interpreted as a consequence of the ongoing merger process as in the case of the non-equilibrium ionization plasma.

  8. Suzaku observations of the merging galaxy cluster Abell 2255: The northeast radio relic

    NASA Astrophysics Data System (ADS)

    Akamatsu, H.; Mizuno, M.; Ota, N.; Zhang, Y.-Y.; van Weeren, R. J.; Kawahara, H.; Fukazawa, Y.; Kaastra, J. S.; Kawaharada, M.; Nakazawa, K.; Ohashi, T.; Röttgering, H. J. A.; Takizawa, M.; Vink, J.; Zandanel, F.

    2017-04-01

    We present the results of deep 140 ks Suzaku X-ray observations of the north-east (NE) radio relic of the merging galaxy cluster Abell 2255. The temperature structure of Abell 2255 is measured out to 0.9 times the virial radius (1.9 Mpc) in the NE direction for the first time. The Suzaku temperature map of the central region suggests a complex temperature distribution, which agrees with previous work. Additionally, on a larger-scale, we confirm that the temperature drops from 6 keV around the cluster center to 3 keV at the outskirts, with two discontinuities at r 5' (450 kpc) and 12' (1100 kpc) from the cluster center. Their locations coincide with surface brightness discontinuities marginally detected in the XMM-Newton image, which indicates the presence of shock structures. From the temperature drop, we estimate the Mach numbers to be ℳinner 1.2 and, ℳouter 1.4. The first structure is most likely related to the large cluster core region ( 350-430 kpc), and its Mach number is consistent with the XMM-Newton observation (ℳ 1.24: Sakelliou & Ponman 2006, MNRAS, 367, 1409). Our detection of the second temperature jump, based on the Suzaku key project observation, shows the presence of a shock structure across the NE radio relic. This indicates a connection between the shock structure and the relativistic electrons that generate radio emission. Across the NE radio relic, however, we find a significantly lower temperature ratio (T1/T2 1.44 ± 0.16 corresponds to ℳX-ray 1.4) than the value expected from radio wavelengths, based on the standard diffusive shock acceleration mechanism (T1/T2> 3.2 or ℳRadio> 2.8). This may suggest that under some conditions, in particular the NE relic of A2255 case, the simple diffusive shock acceleration mechanism is unlikely to be valid, and therefore, more a sophisticated mechanism is required.

  9. Abundance and temperature distributions in the hot intra-cluster gas of Abell 4059

    NASA Astrophysics Data System (ADS)

    Mernier, F.; de Plaa, J.; Lovisari, L.; Pinto, C.; Zhang, Y.-Y.; Kaastra, J. S.; Werner, N.; Simionescu, A.

    2015-03-01

    Using the EPIC and RGS data from a deep (200 ks) XMM-Newton observation, we investigate the temperature structure (kT and σT) and the abundances of nine elements (O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni) of the intra-cluster medium (ICM) in the nearby (z = 0.046) cool-core galaxy cluster Abell 4059. Next to a deep analysis of the cluster core, a careful modelling of the EPIC background allows us to build radial profiles up to 12' (~650 kpc) from the core. Probably because of projection effects, the temperature ICM is not found to be in single phase, even in the outer parts of the cluster. The abundances of Ne, Si, S, Ar, Ca, and Fe, but also O are peaked towards the core. The elements Fe and O are still significantly detected in the outermost annuli, which suggests that the enrichment by both type Ia and core-collapse SNe started in the early stages of the cluster formation. However, the particularly high Ca/Fe ratio that we find in the core is not well reproduced by the standard SNe yield models. Finally, 2D maps of temperature and Fe abundance are presented and confirm the existence of a denser, colder, and Fe-rich ridge south-west of the core, previously observed by Chandra. The origin of this asymmetry in the hot gas of the cluster core is still unclear, but it might be explained by a past intense ram-pressure stripping event near the central cD galaxy. Appendices are available in electronic form at http://www.aanda.org

  10. Linking star formation and galaxy kinematics in the massive cluster Abell 2163

    NASA Astrophysics Data System (ADS)

    Menacho, Veronica; Verdugo, Miguel

    2015-02-01

    The origin of the morphology-density relation is still an open question in galaxy evolution. It is most likely driven by the combination of the efficient star formation in the highest peaks of the mass distribution at high-z and the transformation by environmental processes at later times as galaxies fall into more massive halos. To gain additional insights about these processes we study the kinematics, star formation and structural properties of galaxies in Abell 2163 a very massive (~4×1015 M⊙, Holz & Perlmutter 2012) merging cluster at z = 0.2. We use high resolution spectroscopy with VLT/VIMOS to derive rotation curves and dynamical masses for galaxies that show regular kinematics. Galaxies that show irregular rotation are also analysed to study the origin of their distortion. This information is combined with stellar masses and structural parameters obtained from high quality CFHT imaging. From narrow band photometry (2.2m/WFI), centered on the redshifted Hα line, we obtain star formation rates. Although our sample is still small, field and cluster galaxies lie in a similar Tully-Fisher relation as local galaxies. Controlling by additional parameters like SFRs or bulge-to-disk ratio do not affect this result. We find however that ~50% of the cluster galaxies display irregular kinematics in contrast to what is found in the field at similar redshifts (~30%, Böhm et al. 2004) and in agreement with other studies in clusters (e.g. Bösch et al. 2013, Kutdemir et al. 2010) which points out to additional processes operating in clusters that distort the galaxy kinematics.

  11. A multiwavelength view of the galaxy cluster Abell 523 and its peculiar diffuse radio source

    NASA Astrophysics Data System (ADS)

    Girardi, M.; Boschin, W.; Gastaldello, F.; Giovannini, G.; Govoni, F.; Murgia, M.; Barrena, R.; Ettori, S.; Trasatti, M.; Vacca, V.

    2016-03-01

    We study the structure of the galaxy cluster Abell 523 (A523) at z = 0.104 using new spectroscopic data for 132 galaxies acquired at the Telescopio Nazionale Galileo, new photometric data from the Isaac Newton Telescope, and X-ray and radio data from the Chandra and Very Large Array archives. We estimate the velocity dispersion of the galaxy population, σ _V=949_{-60}^{+80} km s-1, and the X-ray temperature of the hot intracluster medium, kT = 5.3 ± 0.3 keV. We infer that A523 is a massive system: M200 ˜ 7-9 × 1014 M⊙. The analysis of the optical data confirms the presence of two subclusters, 0.75 Mpc apart, tracing the SSW-NNE direction and dominated by the two brightest cluster galaxies (BCG1 and BCG2). The X-ray surface brightness is strongly elongated towards the NNE direction, and its peak is clearly offset from both the brightest cluster galaxies (BCGs). We confirm the presence of a 1.3 Mpc large radio halo, elongated in the ESE-WNW direction and perpendicular to the optical/X-ray elongation. We detect a significant radio/X-ray offset and radio polarization, two features which might be the result of a magnetic field energy spread on large spatial scales. A523 is found consistent with most scaling relations followed by clusters hosting radio haloes, but quite peculiar in the Pradio-LX relation: it is underluminous in the X-rays or overluminous in radio. A523 can be described as a binary head-on merger caught after a collision along the SSW-NNE direction. However, minor optical and radio features suggest a more complex cluster structure, with A523 forming at the crossing of two filaments along the SSW-NNE and ESE-WNW directions.

  12. Structure of Abell 1995 from optical and X-ray data: a galaxy cluster with an elongated radio halo

    NASA Astrophysics Data System (ADS)

    Boschin, W.; Girardi, M.; Barrena, R.

    2012-11-01

    Context. Abell 1995 is a puzzling galaxy cluster hosting a powerful radio halo, but it has not yet been recognized as a obvious cluster merger, as usually expected for clusters with diffuse radio emission. Aims: We aim at an exhaustive analysis of the internal structure of Abell 1995 to verify that this cluster is really dynamically relaxed, as reported in previous studies. Methods: We base our analysis on new and archival spectroscopic and photometric data for 126 galaxies in the field of Abell 1995. The study of the hot intracluster medium was performed on X-ray archival data. Results: Based on 87 fiducial cluster members, we have computed the average cluster redshift ⟨z⟩ = 0.322 and the global radial velocity dispersion σV ~ 1300 km s-1. We detect two main optical subclusters separated by 1.5'that cause the known NE-SW elongation of the galaxy distribution and a significant velocity gradient in the same direction. As for the X-ray analysis, we confirm that the intracluster medium is mildly elongated, but we also detect three X-ray peaks. Two X-ray peaks are offset with respect to the two galaxy peaks and lie between them, thus suggesting a bimodal merger caught in a phase of post core-core passage. The third X-ray peak lies between the NE galaxy peak and a third, minor galaxy peak suggesting a more complex merger. The difficulty of separating the two main systems leads to a large uncertainty on the line-of-sight (LOS) velocity separation and the system mass: ΔVrf,LOS = 600-2000 km s-1and Msys = 2-5×1015 h70-1 M⊙, respectively. Simple analytical arguments suggest a merging scenario for Abell 1995, where two main subsystems are seen just after the collision with an intermediate projection angle. Conclusions: The high mass of Abell 1995 and the evidence of merging suggest it is not atypical among clusters with known radio halos. Interestingly, our findings reinforce the previous evidence for the peculiar dichotomy between the dark matter and galaxy

  13. Can standard cosmological models explain the observed Abell cluster bulk flow?

    NASA Technical Reports Server (NTRS)

    Strauss, Michael A.; Cen, Renyue; Ostriker, Jeremiah P.; Laure, Tod R.; Postman, Marc

    1995-01-01

    Lauer and Postman (LP) observed that all Abell clusters with redshifts less than 15,000 km/s appear to be participating in a bulk flow of 689 km/s with respect to the cosmic microwave background. We find this result difficult to reconcile with all popular models for large-scale structure formation that assume Gaussian initial conditions. This conclusion is based on Monte Carlo realizations of the LP data, drawn from large particle-mesh N-body simulations for six different models of the initial power spectrum (standard, tilted, and Omega(sub 0) = 0.3 cold dark matter, and two variants of the primordial baryon isocurvature model). We have taken special care to treat properly the longest-wavelength components of the power spectra. The simulations are sampled, 'observed,' and analyzed as identically as possible to the LP cluster sample. Large-scale bulk flows as measured from clusters in the simulations are in excellent agreement with those measured from the grid: the clusters do not exhibit any strong velocity bias on large scales. Bulk flows with amplitude as large as that reported by LP are not uncommon in the Monte Carlo data stes; the distribution of measured bulk flows before error bias subtraction is rougly Maxwellian, with a peak around 400 km/s. However the chi squared of the observed bulk flow, taking into account the anisotropy of the error ellipsoid, is much more difficult to match in the simulations. The models examined are ruled out at confidence levels between 94% and 98%.

  14. The merger history of the complex cluster Abell 1758: a combined weak lensing and spectroscopic view

    NASA Astrophysics Data System (ADS)

    Monteiro-Oliveira, R.; Cypriano, E. S.; Machado, R. E. G.; Lima Neto, G. B.; Ribeiro, A. L. B.; Sodré, L.; Dupke, R.

    2017-04-01

    We present a weak-lensing and dynamical study of the complex cluster Abell 1758 (A1758, bar{z} = 0.278) supported by hydrodynamical simulations. This cluster is composed of two main structures called A1758N and A1758S. The northern structure is composed of A1758NW and A1758NE, with lensing determined masses of 7.90_{-1.55}^{+1.89} × 1014 M⊙ and 5.49_{-1.33}^{+1.67} × 1014 M⊙, respectively. They show a remarkable feature: while in A1758NW, there is a spatial agreement among weak-lensing mass distribution, intracluster medium and its brightest cluster galaxy (BCG), in A1758NE, the X-ray peak is located 96_{-15}^{+14} arcsec away from the mass peak and BCG positions. Given the detachment between gas and mass, we could use the local surface mass density to estimate an upper limit for the dark matter self-interaction cross-section: σ/m < 5.83 cm2 g-1. Combining our velocity data with hydrodynamical simulations, we have shown that A1758 NW and NE had their closest approach 0.27 Gyr ago and their merger axis is 21° ± 12° from the plane of the sky. In the A1758S system, we have measured a total mass of 4.96_{-1.19}^{+1.08} × 10^{14} M⊙ and, using radial velocity data, we found that the main merger axis is located at 70° ± 4° from the plane of the sky, therefore closest to the line of sight.

  15. The Origin of Dwarf Galaxies in Clusters: The Faint-End Slope of Abell 85 Galaxy Luminosity Function

    NASA Astrophysics Data System (ADS)

    Agulli, I.; Aguerri, J. A. L.; Barrena, R.; Diaferio, A.; Sánchez-Janssen, R.

    2016-10-01

    Dwarf galaxies (Mb>-18) are important because of their cosmological interest as tests of hierarchical theories. The formation of these galaxies is still an open question but red dwarf galaxies are preferentially located in high density environments, indicating that they are end-products of galaxy transformations in clusters. Deep spectroscopic studies of galaxy clusters are needed to put some constraints on dwarf galaxy formation and evolution. We have observed and analyzed Abell 85, a nearby (z = 0.055) and massive cluster down to M*+6, using the MOS instruments VIMOS@VLT and AF2@WHT. The first and powerful tool to study the characteristics of galaxies and compare with different density environments is the galaxy luminosity function. The comparison of the results for Abell 85 with literature outcomes for clusters and field, allows us to conclude that, at least for this cluster, the environment plays a major role in the nature of the faint-end galaxies, transforming blue dwarfs in the field into red ones in the cluster, but not in the formation of the luminosity function slope.

  16. THE RICH GLOBULAR CLUSTER SYSTEM OF ABELL 1689 AND THE RADIAL DEPENDENCE OF THE GLOBULAR CLUSTER FORMATION EFFICIENCY

    SciTech Connect

    Alamo-Martínez, K. A.; González-Lópezlira, R. A.; Blakeslee, J. P.; Côté, P.; Ferrarese, L.; Jee, M. J.; Jordán, A.; Meurer, G. R.; Peng, E. W.; West, M. J.

    2013-09-20

    We study the rich globular cluster (GC) system in the center of the massive cluster of galaxies Abell 1689 (z = 0.18), one of the most powerful gravitational lenses known. With 28 Hubble Space Telescope/Advanced Camera for Surveys orbits in the F814W bandpass, we reach a magnitude I{sub 814} = 29 with ∼>90% completeness and sample the brightest ∼5% of the GC system. Assuming the well-known Gaussian form of the GC luminosity function (GCLF), we estimate a total population of N{sup total}{sub GC}= 162,850{sup +75,450}{sub -51,310} GCs within a projected radius of 400 kpc. As many as half of the GCs may comprise an intracluster component. Even with the sizable uncertainties, which mainly result from the uncertain GCLF parameters, this system is by far the largest GC population studied to date. The specific frequency S{sub N} is high, but not uncommon for central galaxies in massive clusters, rising from S{sub N} ≈ 5 near the center to ∼12 at large radii. Passive galaxy fading would increase S{sub N} by ∼20% at z = 0. We construct the radial mass profiles of the GCs, stars, intracluster gas, and lensing-derived total mass, and we compare the mass fractions as a function of radius. The estimated mass in GCs, M{sub GC}{sup total} = 3.9 × 10{sup 10} M{sub ☉}, is comparable to ∼80% of the total stellar mass of the Milky Way. The shape of the GC mass profile appears intermediate between those of the stellar light and total cluster mass. Despite the extreme nature of this system, the ratios of the GC mass to the baryonic and total masses, and thus the GC formation efficiency, are typical of those in other rich clusters when comparing at the same physical radii. The GC formation efficiency is not constant, but varies with radius, in a manner that appears similar for different clusters; we speculate on the reasons for this similarity in profile.

  17. Globular Clusters, Ultracompact Dwarfs, and Dwarf Galaxies in Abell 2744 at a Redshift of 0.308

    NASA Astrophysics Data System (ADS)

    Lee, Myung Gyoon; Jang, In Sung

    2016-11-01

    We report a photometric study of globular clusters (GCs), ultracompact dwarfs (UCDs), and dwarf galaxies in the giant merging galaxy cluster Abell 2744 at z = 0.308. Color-magnitude diagrams of the point sources derived from deep F814W (rest frame r‧) and F105W (rest frame I) images of Abell 2744 in the Hubble Space Telescope Frontier Field show a rich population of point sources, which have colors that are similar to those of typical GCs. These sources are as bright as -14.9\\lt {M}r\\prime ≤slant -11.4 (26.0 < F814W(Vega) ≤ 29.5) mag, being mostly UCDs and bright GCs in Abell 2744. The luminosity function (LF) of these sources shows a break at {M}r\\prime ≈ -12.9 (F814W ≈ 28.0) mag, indicating a boundary between UCDs and bright GCs. The numbers of GCs and UCDs are estimated to be 1,711,640+589,760 -430,500 and 147 ± 26, respectively. The clustercentric radial number density profiles of the UCDs and bright GCs show similar slopes, but these profiles are much steeper than those of the dwarf galaxies and the mass density profile based on gravitational lensing analysis. We derive an LF of the red sequence galaxies for -22.9\\lt {M}r\\prime ≤slant -13.9 mag. The faint end of this LF is fit well by a flat power law with α =-1.14+/- 0.08, showing no faint upturn. These results support the galaxy-origin scenario for bright UCDs: they are the nuclei of dwarf galaxies that are stripped when they pass close to the center of massive galaxies or a galaxy cluster, while some of the faint UCDs are at the bright end of the GCs.

  18. Numerical Simulations Challenged on the Prediction of Massive Subhalo Abundance in Galaxy Clusters: The Case of Abell 2142

    NASA Astrophysics Data System (ADS)

    Munari, E.; Grillo, C.; De Lucia, G.; Biviano, A.; Annunziatella, M.; Borgani, S.; Lombardi, M.; Mercurio, A.; Rosati, P.

    2016-08-01

    In this Letter we compare the abundance of the member galaxies of a rich, nearby (z = 0.09) galaxy cluster, Abell 2142, with that of halos of comparable virial mass extracted from sets of state-of-the-art numerical simulations, both collisionless at different resolutions and with the inclusion of baryonic physics in the form of cooling, star formation, and feedback by active galactic nuclei. We also use two semi-analytical models to account for the presence of orphan galaxies. The photometric and spectroscopic information, taken from the Sloan Digital Sky Survey Data Release 12 database, allows us to estimate the stellar velocity dispersion of member galaxies of Abell 2142. This quantity is used as proxy for the total mass of secure cluster members and is properly compared with that of subhalos in simulations. We find that simulated halos have a statistically significant (≳ 7 sigma confidence level) smaller amount of massive (circular velocity above 200 {km} {{{s}}}-1) subhalos, even before accounting for the possible incompleteness of observations. These results corroborate the findings from a recent strong lensing study of the Hubble Frontier Fields galaxy cluster MACS J0416 and suggest that the observed difference is already present at the level of dark matter (DM) subhalos and is not solved by introducing baryonic physics. A deeper understanding of this discrepancy between observations and simulations will provide valuable insights into the impact of the physical properties of DM particles and the effect of baryons on the formation and evolution of cosmological structures.

  19. Optical spectroscopy and the UV luminosity function of galaxies in the Abell 1367, Coma and Virgo clusters

    NASA Astrophysics Data System (ADS)

    Cortese, L.; Gavazzi, G.; Iglesias-Paramo, J.; Boselli, A.; Carrasco, L.

    2003-04-01

    Optical spectroscopy of 93 galaxies, 60 projected in the direction of Abell 1367, 21 onto the Coma cluster and 12 on Virgo, is reported. The targets were selected because they were detected in previous Hα , UV or r' surveys. The present observations bring to 100% the redshift completeness of Hα selected galaxies in the Coma region and to 75% in Abell 1367. All observed galaxies except one show Hα emission and belong to the clusters. This confirms previous determinations of the Hα luminosity function of the two clusters that were based on the assumption that all Hα detected galaxies were cluster members. Using the newly obtained data we re-determine the UV luminosity function of Coma and we compute for the first time the UV luminosity function of A1367. Their faint end slopes remain uncertain (-2.00clusters (Iglesias-Paramo et al. \\cite{lha}). We discover a point-like Hα source in the Virgo cluster, associated with the giant galaxy VCC873, possibly an extragalactic HII region similar to the one recently observed in Virgo by Gerhard et al. (\\cite{Gerhard}). Based on observations obtained with the Loiano telescope belonging to the University of Bologna (Italy), with the G. Haro telescope of the INAOE (Mexico) and with the Calar Alto observatory operated by the Centro Astronomico Hispano Aleman (Spain).

  20. GALAXY AND MASS ASSEMBLY (GAMA): WITNESSING THE ASSEMBLY OF THE CLUSTER ABELL 1882

    SciTech Connect

    Owers, M. S.; Bauer, A. E.; Cluver, M. E.; Hopkins, A. M.; Lara-Lopez, M. A.; Baldry, I. K.; Bland-Hawthorn, J.; Pimbblet, K. A.; Brown, M. J. I.; Colless, M.; Robotham, A. S. G.; Driver, S. P.; Edge, A. C.; Van Kampen, E.; Liske, J.; Loveday, J.; Ponman, T.

    2013-08-01

    We present a combined optical and X-ray analysis of the rich cluster ABELL 1882 (A1882) with the aim of identifying merging substructure and understanding the recent assembly history of this system. Our optical data consist of spectra drawn from the Galaxy and Mass Assembly survey, which lends itself to this kind of detailed study thanks to its depth and high spectroscopic completeness. We use 283 spectroscopically confirmed cluster members to detect and characterize substructure. We complement the optical data with X-ray data taken with both Chandra and XMM. Our analysis reveals that A1882 harbors two main components, A1882A and A1882B, which have a projected separation of {approx}2 Mpc and a line of sight velocity difference of v{sub los}{approx}-428{sup +187}{sub -139} km s{sup -1}. The primary system, A1882A, has velocity dispersion {sigma}{sub v}=500{sub -26}{sup +23} km s{sup -1} and Chandra (XMM) temperature kT = 3.57 {+-} 0.17 keV (3.31{sup +0.28}{sub -0.27} keV) while the secondary, A1882B, has {sigma}{sub v}=457{sup +108}{sub -101} km s{sup -1} and Chandra (XMM) temperature kT = 2.39 {+-} 0.28 keV (2.12 {+-} 0.20 keV). The optical and X-ray estimates for the masses of the two systems are consistent within the uncertainties and indicate that there is twice as much mass in A1882A (M{sub 500} = 1.5-1.9 Multiplication-Sign 10{sup 14} M{sub Sun }) when compared with A1882B (M{sub 500} = 0.8-1.0 Multiplication-Sign 10{sup 14} M{sub Sun }). We interpret the A1882A/A1882B system as being observed prior to a core passage. Supporting this interpretation is the large projected separation of A1882A and A1882B and the dearth of evidence for a recent (<2 Gyr) major interaction in the X-ray data. Two-body analyses indicate that A1882A and A1882B form a bound system with bound incoming solutions strongly favored. We compute blue fractions of f{sub b} = 0.28 {+-} 0.09 and 0.18 {+-} 0.07 for the spectroscopically confirmed member galaxies within r{sub 500} of the centers

  1. Enrichment by supernovae in globular clusters with multiple populations.

    PubMed

    Lee, Jae-Woo; Kang, Young-Woon; Lee, Jina; Lee, Young-Wook

    2009-11-26

    The most massive globular cluster in the Milky Way, omega Centauri, is thought to be the remaining core of a disrupted dwarf galaxy, as expected within the model of hierarchical merging. It contains several stellar populations having different heavy elemental abundances supplied by supernovae-a process known as metal enrichment. Although M 22 appears to be similar to omega Cen, other peculiar globular clusters do not. Therefore omega Cen and M 22 are viewed as exceptional, and the presence of chemical inhomogeneities in other clusters is seen as 'pollution' from the intermediate-mass asymptotic-giant-branch stars expected in normal globular clusters. Here we report Ca abundances for seven globular clusters and compare them to omega Cen. Calcium and other heavy elements can only be supplied through numerous supernovae explosions of massive stars in these stellar systems, but the gravitational potentials of the present-day clusters cannot preserve most of the ejecta from such explosions. We conclude that these globular clusters, like omega Cen, are most probably the relics of more massive primeval dwarf galaxies that merged and disrupted to form the proto-Galaxy.

  2. The XMM Cluster Outskirts Project (X-COP): Physical conditions of Abell 2142 up to the virial radius

    NASA Astrophysics Data System (ADS)

    Tchernin, C.; Eckert, D.; Ettori, S.; Pointecouteau, E.; Paltani, S.; Molendi, S.; Hurier, G.; Gastaldello, F.; Lau, E. T.; Nagai, D.; Roncarelli, M.; Rossetti, M.

    2016-10-01

    Context. Galaxy clusters are continuously growing through the accretion of matter in their outskirts. This process induces inhomogeneities in the gas density distribution (clumping) that need to be taken into account to recover the physical properties of the intracluster medium (ICM) at large radii. Aims: We studied the thermodynamic properties in the outskirts (R > R500) of the massive galaxy cluster Abell 2142 by combining the Sunyaev Zel'dovich (SZ) effect with the X-ray signal. Methods: We combined the SZ pressure profile measured by Planck with the XMM-Newton gas density profile to recover radial profiles of temperature, entropy, and hydrostatic mass out to 2 × R500. We used a method that is insensitive to clumping to recover the gas density, and we compared the results with traditional X-ray measurement techniques. Results: When taking clumping into account, our joint X-SZ entropy profile is consistent with the predictions from pure gravitational collapse, whereas a significant entropy flattening is found when the effect of clumping is neglected. The hydrostatic mass profile recovered using joint X-SZ data agrees with that obtained from spectroscopic X-ray measurements and with mass reconstructions obtained through weak lensing and galaxy kinematics. Conclusions: We found that clumping can explain the entropy flattening observed by Suzaku in the outskirts of several clusters. When using a method that is insensitive to clumping for the reconstruction of the gas density, the thermodynamic properties of Abell 2142 are compatible with the assumption that the thermal gas pressure sustains gravity and that the entropy is injected at accretion shocks, with no need to evoke more exotic physics. Our results highlight the need for X-ray observations with sufficient spatial resolution, and large collecting area, to understand the processes at work in cluster outer regions.

  3. The nearby Abell clusters. II - Luminosity and spatial distribution of galaxies in A2175, A2256, and A2384

    NASA Technical Reports Server (NTRS)

    Oegerle, William R.; Jewison, Michael S.; Hoessel, John G.

    1987-01-01

    The luminosity and spatial distributions of galaxies in the nearby Abell clusters A2175, A2256, and A2384 have been studied using an automated object detection, classification, and photometry system. Schecter functions have been fit to the observed luminosity functions of these clusters. Values of the characteristic magnitude Mr(asterisk) at the 'break' in the luminosity function (LF) are found that are within about 0.25 mag of the so-called 'universal' value of Mr(asterisk) for A2256 and A2384. The faint ends of the LFs of these two clusters are fairly flat, with a value of -1.6 that is steeper than the universal value of -1.25. The spatial distributions of galaxies in all three clusters seem to be described fairly well by power laws, with no evidence for constant-density cores, when the cluster center is assumed to be the central D or cD galaxy. These results indicate a strong correlation between the density distribution of galaxies and the presence of a dominant D or cD galaxy in the cluster.

  4. The near-infrared Tully-Fisher relation - A preliminary study of the Coma and Abell 400 clusters

    NASA Technical Reports Server (NTRS)

    Guhathakurta, Puragra; Bernstein, Gary; Raychaudhury, Somak; Haynes, Martha; Giovanelli, Riccardo; Herter, Terry; Vogt, Nicole

    1993-01-01

    We have started a large project to study the NIR Tully-Fisher (TF) relation using H- and I-band surface photometry of spiral galaxies. A preliminary study of 20 spirals in the Coma and Abell 400 clusters is presented. The NIR images have been used to derive accurate inclinations and total magnitudes, and rotational linewidths are measured from high-quality 21-cm Arecibo data. The scatter in the Coma TF plot is found to be 0.19 mag in the H band and 0.20 mag in the I band for a set of 13 galaxies, if we assume that they are all at the same distance. The deviation of the Coma galaxies from the best-fit Tully-Fisher relation is correlated with their redshift, indicating that some of the galaxies are not bound to the cluster. Indeed, if we treat all the galaxies in the Coma sample as undergoing free Hubble expansion, the TF scatter drops to 0.12 and 0.13 mag for the H- and I-band datasets, respectively. The Abell 400 sample is best fit by a common distance model, yielding a scatter of 0.12 mag for seven galaxies in H using a fixed TF slope. We are in the process of studying cluster and field spirals out to about 10,000 km/s in order to calibrate the NIR TF relation and will apply it to more nearby galaxies to measure the peculiar velocity field in the local universe.

  5. Three Gravitationally Lensed Supernovae Behind Clash Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Patel, Brandon; McCully, Curtis; Jha, Saurbh W.; Rodney, Steven A.; Jones, David O.; Graur, Or; Merten, Julian; Zitrin, Adi; Riess, Adam G.; Matheson, Thomas; Sako, Masao; Holoien, Thomas W. -S.; Postman, Marc; Coe, Dan; Bartelmann, Matthias; Balestra, Italo; Benitez, Narciso; Bouwens, Rychard; Bradley, Larry; Broadhurst, Tom; Cenko, Stephen Bradley; Donahue, Megan; Filippenko, Alexei V.; Ford, Holland; Garnavich, Peter; Grillo, Claudio; Infante, Leopoldo; Jouvel, Stephanie; Kelson, Daniel; Koekemoer, Anton; Lahav, Ofer; Lemze, Doron; Maoz, Dan; Medezinski, Elinor; Melchior, Peter; Meneghetti, Massimo; Molino, Alberto; Moustakas, John; Moustakas, Leonidas A.; Nonino, Mario; Rosati, Piero; Seitz, Stella; Strolger, Louis G.; Umetsu, Keiichi; Zheng, Wei

    2014-01-01

    We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and A383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive. Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was approx. 1.0 +/- 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is approx. 0.2 +/- 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak-lensing maps of the clusters (in magnitude units, 2.5 log10 µ): 0.83 +/- 0.16 mag for SN CLO12Car, 0.28 +/- 0.08 mag for SN CLN12Did, and 0.43 +/- 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.

  6. The Starburst in the Abell 1835 Cluster Central Galaxy: A Case Study of Galaxy Formation Regulated by an Outburst from a Supermassive Black Hole

    NASA Astrophysics Data System (ADS)

    McNamara, B. R.; Rafferty, D. A.; Bîrzan, L.; Steiner, J.; Wise, M. W.; Nulsen, P. E. J.; Carilli, C. L.; Ryan, R.; Sharma, M.

    2006-09-01

    We present an analysis of the starburst in the Abell 1835 cluster's cD galaxy. The dense gas surrounding the galaxy is radiating X-rays at a rate of ~1045 ergs s-1, which is consistent with a cooling rate of ~1000-2000 Msolar yr-1. However, Chandra and XMM-Newton observations found less than 200 Msolar yr-1 of cooling below ~2 keV, a level that is consistent with the cD's current star formation rate of 100-180 Msolar yr-1. One or more heating agents (feedback) must then be replenishing the remaining radiative losses. Supernova explosions and thermal conduction are unable to do so. However, the active galactic nucleus (AGN) is pumping ~=1.4×1045 ergs s-1into the hot gas, which is enough power to offset most of the radiative cooling losses. The AGN jet power exceeds the radio synchrotron power by ~4000 times, making this one of the most radiatively inefficient radio sources known. The jet power implies that the supermassive black hole has accreted at a mean rate of ~0.3 Msolar yr-1 over the last 40 Myr or so, which is a small fraction of the Eddington accretion rate for a ~109 Msolar black hole. The ratio of black hole growth rate by accretion to bulge growth by star formation is consistent with the slope of the (Magorrian) relationship between bulge and central black hole mass in nearby quiescent galaxies. The starburst follows the Schmidt-Kennicutt parameterizations, indicating that the local environment is not substantially altering the IMF and other conditions leading to the onset of star formation. The consistency between net cooling, heating (feedback), and the cooling sink (star formation) in this system resolves the primary objection to traditional cooling flow models.

  7. A compilation of redshifts and velocity dispersions for Abell clusters (Struble and Rood 1987): Documentation for the machine-readable version

    NASA Technical Reports Server (NTRS)

    Warren, Wayne H., Jr.

    1989-01-01

    The machine readable version of the compilation, as it is currently being distributed from the Astronomical Data Center, is described. The catalog contains redshifts and velocity dispersions for all Abell clusters for which these data had been published up to 1986 July. Also included are 1950 equatorial coordinates for the centers of the listed clusters, numbers of observations used to determine the redshifts, and bibliographical references citing the data sources.

  8. Probing the dynamical and X-ray mass proxies of the cluster of galaxies Abell S1101

    NASA Astrophysics Data System (ADS)

    Rabitz, Andreas; Zhang, Yu-Ying; Schwope, Axel; Verdugo, Miguel; Reiprich, Thomas H.; Klein, Matthias

    2017-01-01

    Context. The galaxy cluster Abell S1101 (S1101 hereafter) deviates significantly from the X-ray luminosity versus velocity dispersion relation (L-σ) of galaxy clusters in our previous study. Given reliable X-ray luminosity measurement combining XMM-Newton and ROSAT, this could most likely be caused by the bias in the velocity dispersion due to interlopers and low member statistic in the previous sample of member galaxies, which was solely based on 20 galaxy redshifts drawn from the literature. Aims: We intend to increase the galaxy member statistics to perform precision measurements of the velocity dispersion and dynamical mass of S1101. We aim for a detailed substructure and dynamical state characterization of this cluster, and a comparison of mass estimates derived from (i) the velocity dispersion (Mvir), (ii) the caustic mass computation (Mcaustic), and (iii) mass proxies from X-ray observations and the Sunyaev-Zel'dovich (SZ) effect. Methods: We carried out new optical spectroscopic observations of the galaxies in this cluster field with VIMOS, obtaining a sample of 60 member galaxies for S1101. We revised the cluster redshift and velocity dispersion measurements based on this sample and also applied the Dressler-Shectman substructure test. Results: The completeness of cluster members within r200 was significantly improved for this cluster. Tests for dynamical substructure do not show evidence of major disturbances or merging activities in S1101. We find good agreement between the dynamical cluster mass measurements and X-ray mass estimates, which confirms the relaxed state of the cluster displayed in the 2D substructure test. The SZ mass proxy is slightly higher than the other estimates. The updated measurement of σ erased the deviation of S1101 in the L-σ relation. We also noticed a background structure in the cluster field of S1101. This structure is a galaxy group that is very close to the cluster S1101 in projection but at almost twice its redshift

  9. Application of a XMM-Newton EPIC Monte Carlo to Analysis And Interpretation of Data for Abell 1689, RXJ0658-55 And the Centaurus Clusters of Galaxies

    SciTech Connect

    Andersson, Karl E.; Peterson, J.R.; Madejski, G.M.; /SLAC /KIPAC, Menlo Park

    2007-04-17

    We propose a new Monte Carlo method to study extended X-ray sources with the European Photon Imaging Camera (EPIC) aboard XMM Newton. The Smoothed Particle Inference (SPI) technique, described in a companion paper, is applied here to the EPIC data for the clusters of galaxies Abell 1689, Centaurus and RXJ 0658-55 (the ''bullet cluster''). We aim to show the advantages of this method of simultaneous spectral-spatial modeling over traditional X-ray spectral analysis. In Abell 1689 we confirm our earlier findings about structure in temperature distribution and produce a high resolution temperature map. We also confirm our findings about velocity structure within the gas. In the bullet cluster, RXJ 0658-55, we produce the highest resolution temperature map ever to be published of this cluster allowing us to trace what looks like the motion of the bullet in the cluster. We even detect a south to north temperature gradient within the bullet itself. In the Centaurus cluster we detect, by dividing up the luminosity of the cluster in bands of gas temperatures, a striking feature to the north-east of the cluster core. We hypothesize that this feature is caused by a subcluster left over from a substantial merger that slightly displaced the core. We conclude that our method is very powerful in determining the spatial distributions of plasma temperatures and very useful for systematic studies in cluster structure.

  10. X-ray cavities and temperature jumps in the environment of the strong cool core cluster Abell 2390

    NASA Astrophysics Data System (ADS)

    Sonkamble, S. S.; Vagshette, N. D.; Pawar, P. K.; Patil, M. K.

    2015-10-01

    We present results based on the systematic analysis of high resolution 95 ks Chandra observations of the strong cool core cluster Abell 2390 at the redshift of z = 0.228 that hosts an energetic radio AGN. This analysis has enabled us to investigate five X-ray deficient cavities in the atmosphere of Abell 2390 within central 30''. Presence of these cavities have been confirmed through a variety of image processing techniques like, the surface brightness profiles, unsharp masked image, as well as 2D elliptical model subtracted residual map. Temperature profile as well as 2D temperature map revealed structures in the distribution of ICM, in the sense that ICM in the NW direction is cooler than that on the SE direction. Temperature jump in all directions is evident near 25'' (90.5 kpc) corresponding to the average Mach number 1.44± 0.05, while another jump from 7.47 keV to 9.10 keV at 68'' (246 kpc) in the north-west direction, corresponding to Mach number 1.22± 0.06 and these jumps are associated with the cold fronts. Tricolour map as well as hardness ratio map detects cool gas clumps in the central 30 kpc region of temperature 4.45_{-0.10}^{+0.16} keV. The entropy profile derived from the X-ray analysis is found to fall systematically inward in a power-law fashion and exhibits a floor near 12.20± 2.54 keV cm2 in the central region. This flattening of the entropy profile in the core region confirms the intermittent heating at the centre by AGN. The diffuse radio emission map at 1.4 GHz using VLA L-band data exhibits highly asymmetric morphology with an edge in the north-west direction coinciding with the X-ray edge seen in the unsharp mask image. The mechanical power injected by the AGN in the form of X-ray cavities is found to be 5.94× 10^{45} erg s^{-1} and is roughly an order of magnitude higher than the energy lost by the ICM in the form of X-ray emission, confirming that AGN feedback is capable enough to quench the cooling flow in this cluster.

  11. The kinematics and dynamics of the rich cluster of galaxies Abell 539

    NASA Technical Reports Server (NTRS)

    Ostriker, Eve C.; Huchra, John P.; Geller, Margaret J.; Kurtz, Michael J.

    1988-01-01

    A sample of 289 redshifts within 10 deg of the center of the cluster A539 have been obtained in order to investigate the cluster kinematics and dynamics. Within 1 Mpc of the center, the physical parameters of A539 are found to be typical of those of rich clusters. It is shown that early-type galaxies are more concentrated toward the cluster center and that the velocity distributions of early-type and late-type galaxies differ marginally.

  12. A CHANDRA X-RAY ANALYSIS OF ABELL 1664: COOLING, FEEDBACK, AND STAR FORMATION IN THE CENTRAL CLUSTER GALAXY

    SciTech Connect

    Kirkpatrick, C. C.; McNamara, B. R.; Kazemzadeh, F.; Cavagnolo, K. W.; Rafferty, D. A.; BIrzan, L.; Nulsen, P. E. J.; Wise, M. W.; Gitti, M.

    2009-05-20

    The brightest cluster galaxy (BCG) in the Abell 1664 cluster is unusually blue and is forming stars at a rate of {approx} 23 M {sub sun} yr{sup -1}. The BCG is located within 5 kpc of the X-ray peak, where the cooling time of 3.5 x 10{sup 8} yr and entropy of 10.4 keV cm{sup 2} are consistent with other star-forming BCGs in cooling flow clusters. The center of A1664 has an elongated, 'barlike' X-ray structure whose mass is comparable to the mass of molecular hydrogen, {approx}10{sup 10} M {sub sun} in the BCG. We show that this gas is unlikely to have been stripped from interloping galaxies. The cooling rate in this region is roughly consistent with the star formation rate, suggesting that the hot gas is condensing onto the BCG. We use the scaling relations of BIrzan et al. to show that the active galactic nucleus (AGN) is underpowered compared to the central X-ray cooling luminosity by roughly a factor of three. We suggest that A1664 is experiencing rapid cooling and star formation during a low state of an AGN feedback cycle that regulates the rates of cooling and star formation. Modeling the emission as a single-temperature plasma, we find that the metallicity peaks 100 kpc from the X-ray center, resulting in a central metallicity dip. However, a multi-temperature cooling flow model improves the fit to the X-ray emission and is able to recover the expected, centrally peaked metallicity profile.

  13. The joint far-infrared-optical luminosity function for spiral galaxies and data for the Abell 400 and Cancer clusters

    NASA Technical Reports Server (NTRS)

    Corbelli, Edvige; Salpeter, Edwin E.; Dickey, John M.

    1991-01-01

    Visual and IRAS data for an optically selected sample of 183 late-type galaxies are compiled in tables and graphs and analyzed in detail to determine the joint FIR-optical luminosity function Psi from the FIR/blue luminosity ratio, r = L(FIR)/L(B). It is found that Psi can be approximated by a function of a single variable psi(r-prime), where r-prime is defined as r times L(B)/L(asterisk) exp -delta, with L(asterisk) a constant and delta = about 0.08. A lognormal curve peaking at r-prime = 0.35 and with dispersion of 0.28 is shown to give a good fit to psi(r-prime). From a lack of galaxies with very low r-prime in the present sample it is inferred that there are few spiral galaxies with low interstellar-dust abundances. Also included are data on the distribution function of r-prime for the more distant clusters Abell 400 and Cancer.

  14. Radio emission at the centre of the galaxy cluster Abell 3560: evidence for core sloshing?

    NASA Astrophysics Data System (ADS)

    Venturi, T.; Rossetti, M.; Bardelli, S.; Giacintucci, S.; Dallacasa, D.; Cornacchia, M.; Kantharia, N. G.

    2013-10-01

    Context. We study the interplay between the radio emission associated with the dominant galaxy in clusters and the properties of the surrounding intracluster medium on the basis of its X-ray emission. Aims: Previous radio observations of the galaxy cluster A 3560, located in the Shapley Concentration core, revealed complex radio emission associated with the brightest cluster member. To understand the origin of this radio emission we performed a detailed multiwavelength study with high-quality proprietary data in the radio and X-ray bands and by means of optical data available in the literature. Methods: We observed the cluster with the Giant Metrewave Radio Telescope, the Very Large Array, and the Australia Telescope Compact array at 240 and 610 MHz, 1.28, 1.4, 2.3, 4.8, and 8.4 GHz, and performed a detailed morphological and spectral study of the radio emission associated with the brightest cluster galaxy (BCG). Furthermore, we observed the cluster with the XMM-Newton and Chandra observatories to derive the properties of the intracluster gas. Finally, we made use of literature data to obtain the bidimensional distribution of the galaxies in the cluster. Results: The radio emission, associated with the north-eastern nucleus of the dumb-bell BCG, is the result of two components: an active radio galaxy, with jets and lobes, plus aged diffuse emission, which is not refurbished with new electrons at present. Our Chandra data show that the radio active nucleus of the BCG has extended X-ray emission, which we classify as a low-luminosity corona. A residual image of the XMM-Newton brightness distribution shows a spiral-like feature, which we interpret as the signature of gas sloshing. A sub-group is clearly visible in the surface brightness residual map, and this is also supported by the XMM-Newton temperature analysis. The optical bidimensional analysis shows substructure in A 3560. A galaxy clump was detected at the location of the X-ray sub-group, and another group is

  15. An X-ray and optical study of the cluster of galaxies Abell 754

    NASA Technical Reports Server (NTRS)

    Fabricant, D.; Beers, T. C.; Geller, M. J.; Gorenstein, P.; Huchra, J. P.

    1986-01-01

    X-ray and optical data for A754 are used to study the relative distribution of the luminous and dark matter in this dense, rich cluster of galaxies with X-ray luminosity comparable to that of the Coma Cluster. A quantitative statistical comparison is made of the galaxy positions with the total mass responsible for maintaining the X-ray emitting gas in hydrostatic equilibrium. A simple bimodal model which fits both the X-ray and optical data suggests that the galaxies are distributed consistently with the projected matter distribution within the region covered by the X-ray map (0.5-1 Mpc). The X-ray and optical estimates of the mass in the central region of the cluster are 2.9 x 10 to the 14th and 3.6 + or - 0.5 x 10 to the 14th solar masses, respectively.

  16. The dynamics of the merger in the Frontier Field cluster Abell 2744.

    NASA Astrophysics Data System (ADS)

    Owers, Matt S.

    2015-08-01

    In this talk I will present results from a combined analysis of deep Chandra X-ray observations and a comprehensive redshift survey of the frontier field cluster A2744. From the redshift information, 343 cluster members are selected which are projected within 3 Mpc of the cluster center. Combining positions and velocities, two major substructures are identified, corresponding to the remnants of two major subclusters. The data are consistent with a post-core-passage, major merger taking place along an axis that is tilted well out of the plane of the sky, together with an interloping minor merger. Supporting this interpretation, the X-ray data reveal enriched, low entropy gas from the core of the approaching, major subcluster, lying ~2 north of the cluster center, and a shock front to the southeast of the previously known bright, compact core associated with the receding subcluster. The X-ray morphology of the compact core is consistent with a Bullet-like cluster viewed from within ~45 degrees of the merger axis. An X-ray peak ~3 arcminutes northwest of the cluster center, with an associated cold front to the northeast and a trail of low entropy gas to the south, is interpreted as the remnant of an interloping minor merger taking place roughly in the plane of the sky. The new data taken for the Frontier Fields has allowed precise measurements of the peaks in the projected mass distribution. I will discuss these new results in the context of our redshift and X-ray information and our inferred merger scenario. I will also present preliminary results on the impact of the merger on the galaxy populations bsed on our spectroscopy.

  17. Dynamics of cD Clusters of Galaxies. 4; Conclusion of a Survey of 25 Abell Clusters

    NASA Technical Reports Server (NTRS)

    Oegerle, William R.; Hill, John M.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We present the final results of a spectroscopic study of a sample of cD galaxy clusters. The goal of this program has been to study the dynamics of the clusters, with emphasis on determining the nature and frequency of cD galaxies with peculiar velocities. Redshifts measured with the MX Spectrometer have been combined with those obtained from the literature to obtain typically 50 - 150 observed velocities in each of 25 galaxy clusters containing a central cD galaxy. We present a dynamical analysis of the final 11 clusters to be observed in this sample. All 25 clusters are analyzed in a uniform manner to test for the presence of substructure, and to determine peculiar velocities and their statistical significance for the central cD galaxy. These peculiar velocities were used to determine whether or not the central cD galaxy is at rest in the cluster potential well. We find that 30 - 50% of the clusters in our sample possess significant subclustering (depending on the cluster radius used in the analysis), which is in agreement with other studies of non-cD clusters. Hence, the dynamical state of cD clusters is not different than other present-day clusters. After careful study, four of the clusters appear to have a cD galaxy with a significant peculiar velocity. Dressler-Shectman tests indicate that three of these four clusters have statistically significant substructure within 1.5/h(sub 75) Mpc of the cluster center. The dispersion 75 of the cD peculiar velocities is 164 +41/-34 km/s around the mean cluster velocity. This represents a significant detection of peculiar cD velocities, but at a level which is far below the mean velocity dispersion for this sample of clusters. The picture that emerges is one in which cD galaxies are nearly at rest with respect to the cluster potential well, but have small residual velocities due to subcluster mergers.

  18. A remarkable double-ring galaxy in the cluster Abell 2199

    SciTech Connect

    Pence, W.D.; Oegerle, W.; Borne, K.D. )

    1990-12-01

    B and R CCD images have been obtained of the morphologically peculiar galaxy A1627 + 39, which lies near the center of the rich cluster of galaxies A2199. The galaxy is determined to be a nearly face-on barred S0 galaxy containing two nonconcentric rings. The rings are quite unusual in that they are displaced in opposite directions from the galactic center. There is no color difference across the rings, indicating no recent burst of star formation. Two hypotheses for the origin of the rings have been investigated: (1) a resonance effect with the central bar, and (2) the result of an off-axis, deeply penetrating collision with another cluster member. Models of such a collision are presented, which can reproduce the observed rings. However, neither hypothesis can provide a completely satisfactory explanation of all the observations reported here. 32 refs.

  19. Early-type Galaxies in the Cluster Abell 2390 at z=0.23

    NASA Astrophysics Data System (ADS)

    Fritz, A.; Ziegler, B. L.

    2003-07-01

    A key question of early-type galaxy evolution is when and within what timescales their stellar populations have been formed. In monolithic collapse models a burst of star formation at high redshift (zform>=2) is followed by a passive evolution of the stellar populations, whereas in the hierachical galaxy formation scenario the assembly timescales for more massive galaxies are longer, resulting in somewhat younger mean ages. To investigate the environmental dependence of this question we obtained high-quality spectra of 51 elliptical and lenticular galaxies in the rich cluster A2390 at z=0.23 with MOSCA at the 3.5-m telescope on Calar Alto Observatory. Our investigation spans a wider range in luminosity (M*B+1) than previous spectroscopic studies at intermediate redshift, which were limited to a small number of the more luminous galaxies (apart from the study of Ziegler et al. 2001 MNRAS, 325, 1571 of the cluster A2218 at z=0.18). The evolution of galaxies in age, metallicity and abundance ratios is explored by analysing absorption line strengths, such as H&beta, Mgb, Fe5270 and Fe5335, in comparison with stellar population models. Velocity dispersions (&sigma) are determined to study the slope, scatter and zeropoint of the Faber-Jackson and Mg-&sigma relations. For a subsample of 14 galaxies where morphological and structural parameters are available from HST observations, we also investigate the evolution of the Fundamental Plane. With our large sample it is possible to look for variations in early-type galaxy evolution as a function of distance from the cluster center as well as for different sub-populations like S0 or Balmer-line enhanced galaxies in a statistically significant way.

  20. Unsupervised Clustering of Type II Supernova Light Curves

    NASA Astrophysics Data System (ADS)

    Rubin, Adam; Gal-Yam, Avishay

    2016-09-01

    As new facilities come online, the astronomical community will be provided with extremely large data sets of well-sampled light curves (LCs) of transients. This motivates systematic studies of the LCs of supernovae (SNe) of all types, including the early rising phase. We performed unsupervised k-means clustering on a sample of 59 R-band SN II LCs and find that the rise to peak plays an important role in classifying LCs. Our sample can be divided into three classes: slowly rising (II-S), fast rise/slow decline (II-FS), and fast rise/fast decline (II-FF). We also identify three outliers based on the algorithm. The II-FF and II-FS classes are disjoint in their decline rates, while the II-S class is intermediate and “bridges the gap.” This may explain recent conflicting results regarding II-P/II-L populations. The II-FS class is also significantly less luminous than the other two classes. Performing clustering on the first two principal component analysis components gives equivalent results to using the full LC morphologies. This indicates that Type II LCs could possibly be reduced to two parameters. We present several important caveats to the technique, and find that the division into these classes is not fully robust. Moreover, these classes have some overlap, and are defined in the R band only. It is currently unclear if they represent distinct physical classes, and more data is needed to study these issues. However, we show that the outliers are actually composed of slowly evolving SN IIb, demonstrating the potential of such methods. The slowly evolving SNe IIb may arise from single massive progenitors.

  1. Wavelet transform analysis of the small-scale X-ray structure of the cluster Abell 1367

    NASA Technical Reports Server (NTRS)

    Grebeney, S. A.; Forman, W.; Jones, C.; Murray, S.

    1995-01-01

    We have developed a new technique based on a wavelet transform analysis to quantify the small-scale (less than a few arcminutes) X-ray structure of clusters of galaxies. We apply this technique to the ROSAT position sensitive proportional counter (PSPC) and Einstein high-resolution imager (HRI) images of the central region of the cluster Abell 1367 to detect sources embedded within the diffuse intracluster medium. In addition to detecting sources and determining their fluxes and positions, we show that the wavelet analysis allows a characterization of the sources extents. In particular, the wavelet scale at which a given source achieves a maximum signal-to-noise ratio in the wavelet images provides an estimate of the angular extent of the source. To account for the widely varying point response of the ROSAT PSPC as a function of off-axis angle requires a quantitative measurement of the source size and a comparison to a calibration derived from the analysis of a Deep Survey image. Therefore, we assume that each source could be described as an isotropic two-dimensional Gaussian and used the wavelet amplitudes, at different scales, to determine the equivalent Gaussian Full Width Half-Maximum (FWHM) (and its uncertainty) appropriate for each source. In our analysis of the ROSAT PSPC image, we detect 31 X-ray sources above the diffuse cluster emission (within a radius of 24 min), 16 of which are apparently associated with cluster galaxies and two with serendipitous, background quasars. We find that the angular extents of 11 sources exceed the nominal width of the PSPC point-spread function. Four of these extended sources were previously detected by Bechtold et al. (1983) as 1 sec scale features using the Einstein HRI. The same wavelet analysis technique was applied to the Einstein HRI image. We detect 28 sources in the HRI image, of which nine are extended. Eight of the extended sources correspond to sources previously detected by Bechtold et al. Overall, using both the

  2. The Distance and Mass of the Galaxy Cluster Abell 1995 Derived from Sunyaev-Zeldovich Effect and X-Ray Measurements

    NASA Technical Reports Server (NTRS)

    Patel, Sandeep K.; Joy, Marshall; Carlstrom, John E.; Holder, Gilbert P.; Reese, Erik D.; Gomez, Percy L.; Hughes, John P.; Grego, Laura; Holzapfel, William L.

    2000-01-01

    We present multiwavelength observations of the Abell 1995 galaxy cluster. From an analysis of X-ray spectroscopy and imaging data, we derive the electron temperature, cluster core radius, and central electron number density. Using optical spectroscopy of 15 cluster members, we derive an accurate cluster redshift and velocity dispersion. Finally, the interferometric imaging of the Sunyaev-Zeldovich effect toward Abell 1995 at 28.5 GHz provides a measure of the integrated pressure through the cluster. The X-ray and Sunyaev-Zeldovich effect observations are combined to determine the angular diameter distance to the cluster of D(sub A) = 1294(sup +294 +438, sub -283 -458) Mpc (Statistical followed by systematic uncertainty), implying a Hubble constant of H(sub 0) = 52.2(sup +11.4 +18.5, sub -11.9 -17.7) km/s.Mpc for Omega(sub M) = 0.3 and Omega(sub lambda) = 0.7. We find a best-fit H(sub 0) of 46 km/s.Mpc for the Omega(sub M) = 1 and Omega(sub lambda) = 0 cosmology, and 48 km/s.Mpc for Omega(sub M) = 0.3 and Omega(sub lambda) = 0.0. The X-ray data are also used to derive a total cluster mass of M(sup HSE, sub tot)(r(sub 500)) = 5.18(sup +0.62, sub -0.48) x 10(exp 14)/h solar mass; the optical velocity dispersion yields an independent and consistent estimate of M(sup virial, sub tot)(r(sub 500)) = 6.35(sup +1.51, sub -1.19) X 10(exp 14) /h solar mass. Both of the total mass estimates are evaluated at a fiducial radius, r(sub 500) = 830 /h kpc, where the overdensity is 500 times the critical density. The total cluster mass is then combined with gas mass measurements to determine a cluster gas mass fraction of F(sub g) = 0.056(sup +0.010, sub -0.013) /h(sup 3/2) in combination with recent baryon density constraints, the measured gas mass fraction yields an upper limit on the mass density parameter of Omega(sub M) h(sup 1/2) <= 0.34(sup +/0.06, sub 0.05.

  3. A runaway collision in a young star cluster as the origin of the brightest supernova.

    PubMed

    Portegies Zwart, Simon F; van den Heuvel, Edward P J

    2007-11-15

    Supernova SN 2006gy in the galaxy NGC 1260 is the most luminous recorded. Its progenitor might have been a very massive (>100 Mo, where is the mass of the Sun) star, but that interpretation is incompatible with hydrogen in the spectrum of the supernova; stars >40 Moare believed to have shed their hydrogen envelopes several hundred thousand years before the explosion. Alternatively, the progenitor might have arisen from the merger of two massive stars. Here we show that the collision frequency of massive stars in a dense and young cluster (of the kind to be expected near the centre of a galaxy) is sufficient to provide a reasonable chance that SN 2006gy resulted from such a bombardment. If this is the correct explanation, then we predict that when the supernova fades (in a year or so) a dense cluster of massive stars will become visible at the site of the explosion.

  4. The First Murchison Widefield Array low-frequency radio observations of cluster scale non-thermal emission: the case of Abell 3667

    NASA Astrophysics Data System (ADS)

    Hindson, L.; Johnston-Hollitt, M.; Hurley-Walker, N.; Buckley, K.; Morgan, J.; Carretti, E.; Dwarakanath, K. S.; Bell, M.; Bernardi, G.; Bhat, N. D. R.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Jacobs, D.; Kaplan, D. L.; Kasper, J. C.; Kratzenberg, E.; Kudryavtseva, N.; Lenc, E.; Lonsdale, C. J.; Lynch, M. J.; McWhirter, S. R.; McKinley, B.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Pindor, B.; Prabu, T.; Procopio, P.; Offringa, A. R.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.

    2014-11-01

    We present the first Murchison Widefield Array observations of the well-known cluster of galaxies Abell 3667 (A3667) between 105 and 241 MHz. A3667 is one of the best known examples of a galaxy cluster hosting a double radio relic and has been reported to contain a faint radio halo and bridge. The origin of radio haloes, relics and bridges is still unclear, however galaxy cluster merger seems to be an important factor. We clearly detect the north-west (NW) and south-east radio relics in A3667 and find an integrated flux density at 149 MHz of 28.1 ± 1.7 and 2.4 ± 0.1 Jy, respectively, with an average spectral index, between 120 and 1400 MHz, of -0.9 ± 0.1 for both relics. We find evidence of a spatial variation in the spectral index across the NW relic steepening towards the centre of the cluster, which indicates an ageing electron population. These properties are consistent with higher frequency observations. We detect emission that could be associated with a radio halo and bridge. However, due to the presence of poorly sampled large-scale Galactic emission and blended point sources we are unable to verify the exact nature of these features.

  5. Astrophysics. Multiple images of a highly magnified supernova formed by an early-type cluster galaxy lens.

    PubMed

    Kelly, Patrick L; Rodney, Steven A; Treu, Tommaso; Foley, Ryan J; Brammer, Gabriel; Schmidt, Kasper B; Zitrin, Adi; Sonnenfeld, Alessandro; Strolger, Louis-Gregory; Graur, Or; Filippenko, Alexei V; Jha, Saurabh W; Riess, Adam G; Bradac, Marusa; Weiner, Benjamin J; Scolnic, Daniel; Malkan, Matthew A; von der Linden, Anja; Trenti, Michele; Hjorth, Jens; Gavazzi, Raphael; Fontana, Adriano; Merten, Julian C; McCully, Curtis; Jones, Tucker; Postman, Marc; Dressler, Alan; Patel, Brandon; Cenko, S Bradley; Graham, Melissa L; Tucker, Bradley E

    2015-03-06

    In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery of such a system. In Hubble Space Telescope imaging, we have found four images of a single supernova forming an Einstein cross configuration around a redshift z = 0.54 elliptical galaxy in the MACS J1149.6+2223 cluster. The cluster's gravitational potential also creates multiple images of the z = 1.49 spiral supernova host galaxy, and a future appearance of the supernova elsewhere in the cluster field is expected. The magnifications and staggered arrivals of the supernova images probe the cosmic expansion rate, as well as the distribution of matter in the galaxy and cluster lenses.

  6. Supernova Candidate in MACSJ1149 Galaxy Cluster Field With No Detected Host Galaxy

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick L.; Diego, Jose Maria; Nonino, Mario; Zitrin, Adi; Jauzac, Mathilde; Filippenko, Alexei V.

    2017-01-01

    We report discovery of a supernova (SN) candidate in the MACSJ1149 (z=0.54) galaxy-cluster field. In Hubble Space Telescope (HST) data taken on January 23, 2017 UT, we found a bright source (dubbed 'Amos') in WFC3 UVIS F606W ( 23.3 mag AB) and WFC3 IR F110W ( 23.7 mag) exposures.

  7. Hubble Frontier Fields: a high-precision strong-lensing analysis of the massive galaxy cluster Abell 2744 using ˜180 multiple images

    NASA Astrophysics Data System (ADS)

    Jauzac, M.; Richard, J.; Jullo, E.; Clément, B.; Limousin, M.; Kneib, J.-P.; Ebeling, H.; Natarajan, P.; Rodney, S.; Atek, H.; Massey, R.; Eckert, D.; Egami, E.; Rexroth, M.

    2015-09-01

    We present a high-precision mass model of galaxy cluster Abell 2744, based on a strong gravitational-lensing analysis of the Hubble Space Telescope Frontier Fields (HFF) imaging data, which now include both Advanced Camera for Surveys and Wide Field Camera 3 observations to the final depth. Taking advantage of the unprecedented depth of the visible and near-infrared data, we identify 34 new multiply imaged galaxies, bringing the total to 61, comprising 181 individual lensed images. In the process, we correct previous erroneous identifications and positions of multiple systems in the northern part of the cluster core. With the LENSTOOL software and the new sets of multiple images, we model the cluster using two cluster-scale dark matter haloes plus galaxy-scale haloes for the cluster members. Our best-fitting model predicts image positions with an rms error of 0.79 arcsec, which constitutes an improvement by almost a factor of 2 over previous parametric models of this cluster. We measure the total projected mass inside a 200 kpc aperture as (2.162 ± 0.005) × 1014 M⊙, thus reaching 1 per cent level precision for the second time, following the recent HFF measurement of MACSJ0416.1-2403. Importantly, the higher quality of the mass model translates into an overall improvement by a factor of 4 of the derived magnification factor. Together with our previous HFF gravitational lensing analysis, this work demonstrates that the HFF data enables high-precision mass measurements for massive galaxy clusters and the derivation of robust magnification maps to probe the early Universe.

  8. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    SciTech Connect

    Dilday, Benjamin; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter; Goobar, Ariel; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  9. A MEASUREMENT OF THE RATE OF TYPE Ia SUPERNOVAE IN GALAXY CLUSTERS FROM THE SDSS-II SUPERNOVA SURVEY

    SciTech Connect

    Dilday, Benjamin; Jha, Saurabh W.; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Hopp, Ulrich; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, LluIs; Miquel, Ramon; Garnavich, Peter; Goobar, Ariel; Ihara, Yutaka; Kessler, Richard; Lampeitl, Hubert; Nichol, Robert C.; Marriner, John; Molla, Mercedes

    2010-06-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {<=} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {<=} z {<=} 0.3. We find values for the cluster SN Ia rate of (0.37{sup +0.17+0.01} {sub -0.12-0.01}) SNur h {sup 2} and (0.55{sup +0.13+0.02} {sub -0.11-0.01}) SNur h {sup 2} (SNux = 10{sup -12} L {sup -1} {sub xsun} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sup +0.18+0.01} {sub -0.12-0.01}) SNur h {sup 2} and (0.49{sup +0.15+0.02} {sub -0.11-0.01}) SNur h {sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sup +1.99+0.07} {sub -1.11-0.04}) SNur h {sup 2} and (0.36{sup +0.84+0.01} {sub -0.30-0.01}) SNur h {sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sup +1.31+0.043} {sub -0.91-0.015} and 3.02{sup +1.31+0.062} {sub -1.03-0.048}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sup +0.15} {sub -0.14})+(0.91{sup +0.85} {sub -0.81}) x z] SNuB h {sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most three hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe

  10. Gemini Frontier Fields: Wide-field Adaptive Optics Ks-band Imaging of the Galaxy Clusters MACS J0416.1-2403 and Abell 2744

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Carrasco, E. R.; Pessev, P.; Garrel, V.; Winge, C.; Neichel, B.; Vidal, F.

    2015-04-01

    We have observed two of the six Frontier Fields galaxy clusters, MACS J0416.1-2403 and Abell 2744, using the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI). With 0.″ 08-0.″ 10 FWHM our data are nearly diffraction-limited over a 100\\prime\\prime × 100\\prime\\prime wide area. GeMS/GSAOI complements the Hubble Space Telescope (HST) redwards of 1.6 μm with twice the angular resolution. We reach a 5σ depth of {{K}s}˜ 25.6 mag (AB) for compact sources. In this paper, we describe the observations, data processing, and initial public data release. We provide fully calibrated, co-added images matching the native GSAOI pixel scale as well as the larger plate scales of the HST release, adding to the legacy value of the Frontier Fields. Our work demonstrates that even for fields at high galactic latitude where natural guide stars are rare, current multi-conjugated adaptive optics technology at 8 m telescopes has opened a new window on the distant universe. Observations of a third Frontier Field, Abell 370, are planned. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Based on observations made with ESO Telescopes at the La Silla and Paranal Observatories, Chile.

  11. Substructure lensing in galaxy clusters as a constraint on low-mass sterile neutrinos in tensor-vector-scalar theory: The straight arc of Abell 2390

    SciTech Connect

    Feix, Martin; Zhao Hongsheng; Fedeli, Cosimo; Hoekstra, Henk

    2010-12-15

    Certain covariant theories of the modified Newtonian dynamics paradigm seem to require an additional hot dark matter (HDM) component--in the form of either heavy ordinary neutrinos or more recently light sterile neutrinos (SNs) with a mass around 11 eV--to be relieved of problems ranging from cosmological scales down to intermediate ones relevant for galaxy clusters. Here we suggest using gravitational lensing by galaxy clusters to test such a marriage of neutrino HDM and modified gravity, adopting the framework of tensor-vector-scalar theory (TeVeS). Unlike conventional cold dark matter (CDM), such HDM is subject to strong phase-space constraints, which allows one to check cluster lens models inferred within the modified framework for consistency. Since the considered HDM particles cannot collapse into arbitrarily dense clumps and only form structures well above the galactic scale, systems which indicate the need for dark substructure are of particular interest. As a first example, we study the cluster lens Abell 2390 and its impressive straight arc with the help of numerical simulations. Based on our results, we outline a general and systematic approach to model cluster lenses in TeVeS which significantly reduces the calculation complexity. We further consider a simple bimodal lens configuration, capable of producing the straight arc, to demonstrate our approach. We find that such a model is marginally consistent with the hypothesis of 11 eV SNs. Future work including more detailed and realistic lens models may further constrain the necessary SN distribution and help to conclusively assess this point. Cluster lenses could therefore provide an interesting discriminator between CDM and such modified gravity scenarios supplemented by SNs or other choices of HDM.

  12. Substructure lensing in galaxy clusters as a constraint on low-mass sterile neutrinos in tensor-vector-scalar theory: The straight arc of Abell 2390

    NASA Astrophysics Data System (ADS)

    Feix, Martin; Zhao, Hongsheng; Fedeli, Cosimo; Pestaña, José Luis Garrido; Hoekstra, Henk

    2010-12-01

    Certain covariant theories of the modified Newtonian dynamics paradigm seem to require an additional hot dark matter (HDM) component—in the form of either heavy ordinary neutrinos or more recently light sterile neutrinos (SNs) with a mass around 11 eV—to be relieved of problems ranging from cosmological scales down to intermediate ones relevant for galaxy clusters. Here we suggest using gravitational lensing by galaxy clusters to test such a marriage of neutrino HDM and modified gravity, adopting the framework of tensor-vector-scalar theory (TeVeS). Unlike conventional cold dark matter (CDM), such HDM is subject to strong phase-space constraints, which allows one to check cluster lens models inferred within the modified framework for consistency. Since the considered HDM particles cannot collapse into arbitrarily dense clumps and only form structures well above the galactic scale, systems which indicate the need for dark substructure are of particular interest. As a first example, we study the cluster lens Abell 2390 and its impressive straight arc with the help of numerical simulations. Based on our results, we outline a general and systematic approach to model cluster lenses in TeVeS which significantly reduces the calculation complexity. We further consider a simple bimodal lens configuration, capable of producing the straight arc, to demonstrate our approach. We find that such a model is marginally consistent with the hypothesis of 11 eV SNs. Future work including more detailed and realistic lens models may further constrain the necessary SN distribution and help to conclusively assess this point. Cluster lenses could therefore provide an interesting discriminator between CDM and such modified gravity scenarios supplemented by SNs or other choices of HDM.

  13. THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). IV. MASS RECONSTRUCTION OF THE LENSING CLUSTER ABELL 2744 FROM FRONTIER FIELD IMAGING AND GLASS SPECTROSCOPY

    SciTech Connect

    Wang, X.; Schmidt, K. B.; Jones, T. A.; Hoag, A.; Huang, K.-H.; Bradac, M.; Treu, T.; Brammer, G. B.; Ryan, R. E. Jr.; Vulcani, B.; Amorín, R.; Castellano, M.; Fontana, A.; Merlin, E.; Trenti, M.

    2015-09-20

    We present a strong and weak lensing reconstruction of the massive cluster Abell 2744, the first cluster for which deep Hubble Frontier Fields (HFF) images and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are available. By performing a targeted search for emission lines in multiply imaged sources using the GLASS spectra, we obtain five high-confidence spectroscopic redshifts and two tentative ones. We confirm one strongly lensed system by detecting the same emission lines in all three multiple images. We also search for additional line emitters blindly and use the full GLASS spectroscopic catalog to test reliability of photometric redshifts for faint line emitters. We see a reasonable agreement between our photometric and spectroscopic redshift measurements, when including nebular emission in photometric redshift estimations. We introduce a stringent procedure to identify only secure multiple image sets based on colors, morphology, and spectroscopy. By combining 7 multiple image systems with secure spectroscopic redshifts (at 5 distinct redshift planes) with 18 multiple image systems with secure photometric redshifts, we reconstruct the gravitational potential of the cluster pixellated on an adaptive grid, using a total of 72 images. The resulting mass map is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data to study the relative distribution of stars and dark matter in the cluster. We find that the stellar to total mass ratio varies substantially across the cluster field, suggesting that stars do not trace exactly the total mass in this interacting system. The maps of convergence, shear, and magnification are made available in the standard HFF format.

  14. The Grism Lens-amplified Survey from Space (GLASS). IV. Mass Reconstruction of the Lensing Cluster Abell 2744 from Frontier Field Imaging and GLASS Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, X.; Hoag, A.; Huang, K.-H.; Treu, T.; Bradač, M.; Schmidt, K. B.; Brammer, G. B.; Vulcani, B.; Jones, T. A.; Ryan, R. E., Jr.; Amorín, R.; Castellano, M.; Fontana, A.; Merlin, E.; Trenti, M.

    2015-09-01

    We present a strong and weak lensing reconstruction of the massive cluster Abell 2744, the first cluster for which deep Hubble Frontier Fields (HFF) images and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are available. By performing a targeted search for emission lines in multiply imaged sources using the GLASS spectra, we obtain five high-confidence spectroscopic redshifts and two tentative ones. We confirm one strongly lensed system by detecting the same emission lines in all three multiple images. We also search for additional line emitters blindly and use the full GLASS spectroscopic catalog to test reliability of photometric redshifts for faint line emitters. We see a reasonable agreement between our photometric and spectroscopic redshift measurements, when including nebular emission in photometric redshift estimations. We introduce a stringent procedure to identify only secure multiple image sets based on colors, morphology, and spectroscopy. By combining 7 multiple image systems with secure spectroscopic redshifts (at 5 distinct redshift planes) with 18 multiple image systems with secure photometric redshifts, we reconstruct the gravitational potential of the cluster pixellated on an adaptive grid, using a total of 72 images. The resulting mass map is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data to study the relative distribution of stars and dark matter in the cluster. We find that the stellar to total mass ratio varies substantially across the cluster field, suggesting that stars do not trace exactly the total mass in this interacting system. The maps of convergence, shear, and magnification are made available in the standard HFF format.

  15. Type-Ia Supernova Rates to Redshift 2.4 from Clash: The Cluster Lensing and Supernova Survey with Hubble

    NASA Technical Reports Server (NTRS)

    Graur, O.; Rodney, S. A.; Maoz, D.; Riess, A. G.; Jha, S. W.; Postman, M.; Dahlen, T.; Holoien, T. W.-S.; McCully, C.; Patel, B.; Strolger, L.-G.; Benitez, N.; Coe, D.; Jouvel, S.; Medezinski, E.; Molino, A.; Nonino, M.; Bradley, L.; Koehemoer, A.; Balestra, I.; Cenko, S. B.; Clubb, K. I.; Dickinson, M. E.; Filippenko, A. V.; Frederiksen, T. F.; Garnavich, P.; Hjorth, J.; Jones, D. O.; Leibundgut, B.; Matheson, T.; Mobasher, B.; Rosati, P.; Silverman, J. M.; U., V.; Jedruszczuk, K.

    2014-01-01

    We present the supernova (SN) sample and Type-Ia SN (SN Ia) rates from the Cluster Lensing And Supernova survey with Hubble (CLASH). Using the Advanced Camera for Surveys and the Wide Field Camera 3 on the Hubble Space Telescope (HST), we have imaged 25 galaxy-cluster fields and parallel fields of non-cluster galaxies. We report a sample of 27 SNe discovered in the parallel fields. Of these SNe, approximately 13 are classified as SN Ia candidates, including four SN Ia candidates at redshifts z greater than 1.2.We measure volumetric SN Ia rates to redshift 1.8 and add the first upper limit on the SN Ia rate in the range z greater than 1.8 and less than 2.4. The results are consistent with the rates measured by the HST/ GOODS and Subaru Deep Field SN surveys.We model these results together with previous measurements at z less than 1 from the literature. The best-fitting SN Ia delay-time distribution (DTD; the distribution of times that elapse between a short burst of star formation and subsequent SN Ia explosions) is a power law with an index of 1.00 (+0.06(0.09))/(-0.06(0.10)) (statistical) (+0.12/-0.08) (systematic), where the statistical uncertainty is a result of the 68% and 95% (in parentheses) statistical uncertainties reported for the various SN Ia rates (from this work and from the literature), and the systematic uncertainty reflects the range of possible cosmic star-formation histories. We also test DTD models produced by an assortment of published binary population synthesis (BPS) simulations. The shapes of all BPS double-degenerate DTDs are consistent with the volumetric SN Ia measurements, when the DTD models are scaled up by factors of 3-9. In contrast, all BPS single-degenerate DTDs are ruled out by the measurements at greater than 99% significance level.

  16. A radio survey of clusters of galaxies. V - 11.1 CM maps of 18 Abell Clusters and observations of selected sources at 6.3 and 2.8 CM

    NASA Astrophysics Data System (ADS)

    Andernach, H.; Sievers, A.; Kus, A.; Schnaubelt, J.

    1986-09-01

    Thirteen areas containing eighteen rich clusters of galaxies have been mapped in radio continuum at λ11.1 cm with the 100-m Effelsberg telescope. The angular resolution is 4arcmin.4. Linear polarization was also recorded for some of the fields, which in most cases extend to the full Abell radius of the clusters. A few of the more complex sources in these fields have been additionally observed at λ6.3 cm and, for the first time in this series of papers, also at λ2.8 cm to study their structure and spectral variations. A total of 142 sources are reported here. Optical identifications are proposed for nearly half of the detected sources.

  17. Supernovae

    NASA Astrophysics Data System (ADS)

    March, Marisa

    2014-03-01

    We live in a Universe that is getting bigger faster. This astonishing discovery of Universal acceleration was made in the late 1990s by two teams who made observations of a special type of exploded star known as a `Supernova Type Ia'. (SNeIa) Since the discovery of the accelerating Universe, one of the biggest questions in modern cosmology has been to determine the cause of that acceleration - the answer to this question will have far reaching implications for our theories of cosmology and fundamental physics more broadly. The two main competing explanations for this apparent late time acceleration of the Universe are modified gravity and dark energy. The Dark Energy Survey (DES) has been designed and commissioned to find to find answers to these questions about the nature of dark energy and modified gravity. The new 570 megapixel Dark Energy Camera is currently operating with the Cerro-Tololo Inter American Observatory's 4m Blanco teleccope, carrying out a systematic search for SNeIa, and mapping out the large scale structure of the Universe by making observations of galaxies. The DES science program program which saw first light in September 2013 will run for five years in total. DES SNeIa data in combination with the other DES observations of large scale structure will enable us to put increasingly accurate constraints on the expansion history of the Universe and will help us distinguish between competing theories of dark energy and modified gravity. As we draw to the close of the first observing season of DES in March 2014, we will report on the current status of the DES supernova survey, presenting first year supernovae data, preliminary results, survey strategy, discovery pipeline, spectroscopic target selection and data quality. This talk will give the first glimpse of the DES SN first year data and initial results as we begin our five year survey in search of dark energy. On behalf of the Dark Energy Survey collaboration.

  18. SUPERNOVAE AND THEIR EXPANDING BLAST WAVES DURING THE EARLY EVOLUTION OF GALACTIC GLOBULAR CLUSTERS

    SciTech Connect

    Tenorio-Tagle, Guillermo; Silich, Sergiy; Muñoz-Tuñón, Casiana; Cassisi, Santi E-mail: cmt@iac.es

    2015-11-20

    Our arguments deal with the early evolution of Galactic globular clusters and show why only a few of the supernovae (SNe) products were retained within globular clusters and only in the most massive cases (M ≥ 10{sup 6} M{sub ⊙}), while less massive clusters were not contaminated at all by SNe. Here, we show that SN blast waves evolving in a steep density gradient undergo blowout and end up discharging their energy and metals into the medium surrounding the clusters. This inhibits the dispersal and the contamination of the gas left over from a first stellar generation. Only the ejecta from well-centered SNe that evolve into a high-density medium available for a second stellar generation (2SG) in the most massive clusters would be retained. These are likely to mix their products with the remaining gas, eventually leading in these cases to an Fe-contaminated 2SG.

  19. The influence of inelastic neutrino interactions with light clusters on core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi

    2014-12-01

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light clusters in hot nuclear matter on core-collapse supernova simulations. These interactions have been neglected in most hydrodynamical supernova simulations. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged- current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. We show that the heating rates of deuterons reach as high as ~ 10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light clusters have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light clusters, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.

  20. Dusty supernovae running the thermodynamics of the matter reinserted within young and massive super stellar clusters

    SciTech Connect

    Tenorio-Tagle, Guillermo; Silich, Sergiy; Martínez-González, Sergio; Muñoz-Tuñón, Casiana; Palouš, Jan; Wünsch, Richard E-mail: cmt@ll.iac.es

    2013-12-01

    Following the observational and theoretical evidence that points at core-collapse supernovae (SNe) as major producers of dust, here we calculate the hydrodynamics of the matter reinserted within young and massive super stellar clusters under the assumption of gas and dust radiative cooling. The large SN rate expected in massive clusters allows for a continuous replenishment of dust immersed in the high temperature thermalized reinserted matter and warrants a stationary presence of dust within the cluster volume during the type II SN era. We first show that such a balance determines the range of the dust-to-gas-mass ratio, and thus the dust cooling law. We then search for the critical line that separates stationary cluster winds from the bimodal cases in the cluster mechanical luminosity (or cluster mass) versus cluster size parameter space. In the latter, strong radiative cooling reduces considerably the cluster wind mechanical energy output and affects particularly the cluster central regions, leading to frequent thermal instabilities that diminish the pressure and inhibit the exit of the reinserted matter. Instead, matter accumulates there and is expected to eventually lead to gravitational instabilities and to further stellar formation with the matter reinserted by former massive stars. The main outcome of the calculations is that the critical line is almost two orders of magnitude or more, depending on the assumed value of V {sub A∞}, lower than when only gas radiative cooling is applied. And thus, many massive clusters are predicted to enter the bimodal regime.

  1. MASS SUBSTRUCTURE IN ABELL 3128

    SciTech Connect

    McCleary, J.; Dell’Antonio, I.; Huwe, P.

    2015-05-20

    We perform a detailed two-dimensional weak gravitational lensing analysis of the nearby (z = 0.058) galaxy cluster Abell 3128 using deep ugrz imaging from the Dark Energy Camera (DECam). We have designed a pipeline to remove instrumental artifacts from DECam images and stack multiple dithered observations without inducing a spurious ellipticity signal. We develop a new technique to characterize the spatial variation of the point-spread function that enables us to circularize the field to better than 0.5% and thereby extract the intrinsic galaxy ellipticities. By fitting photometric redshifts to sources in the observation, we are able to select a sample of background galaxies for weak-lensing analysis free from low-redshift contaminants. Photometric redshifts are also used to select a high-redshift galaxy subsample with which we successfully isolate the signal from an interloping z = 0.44 cluster. We estimate the total mass of Abell 3128 by fitting the tangential ellipticity of background galaxies with the weak-lensing shear profile of a Navarro–Frenk–White (NFW) halo and also perform NFW fits to substructures detected in the 2D mass maps of the cluster. This study yields one of the highest resolution mass maps of a low-z cluster to date and is the first step in a larger effort to characterize the redshift evolution of mass substructures in clusters.

  2. ROSAT HRI images of Abell 85 and Abell 496: Evidence for inhomogeneities in cooling flows

    NASA Technical Reports Server (NTRS)

    Prestwich, Andrea H.; Guimond, Stephen J.; Luginbuhl, Christian; Joy, Marshall

    1994-01-01

    We present ROSAT HRI images of two clusters of galaxies with cooling flows, Abell 496 and Abell 85. In these clusters, x-ray emission on small scales above the general cluster emission is significant at the 3 sigma level. There is no evidence for optical counterparts. The enhancements may be associated with lumps of gas at a lower temperature and higher density than the ambient medium, or hotter, denser gas perhaps compressed by magnetic fields. These observations can be used to test models of how thermal instabilities form and evolve in cooling flows.

  3. CLASH-VLT: Environment-driven evolution of galaxies in the z = 0.209 cluster Abell 209

    NASA Astrophysics Data System (ADS)

    Annunziatella, M.; Mercurio, A.; Biviano, A.; Girardi, M.; Nonino, M.; Balestra, I.; Rosati, P.; Bartosch Caminha, G.; Brescia, M.; Gobat, R.; Grillo, C.; Lombardi, M.; Sartoris, B.; De Lucia, G.; Demarco, R.; Frye, B.; Fritz, A.; Moustakas, J.; Scodeggio, M.; Kuchner, U.; Maier, C.; Ziegler, B.

    2016-01-01

    Context. The analysis of galaxy properties, such as stellar masses, colors, sizes and morphologies, and the relations among them and the environment, in which the galaxies reside, can be used to investigate the physical processes driving galaxy evolution. Aims: We conduct a thorough study of the cluster A209 with a new large spectro-photometric dataset to investigate possible environmental effects on galaxy properties that can provide information on galaxy evolution in cluster hostile environments. Methods: We use the dataset obtained as part of the CLASH-VLT spectroscopic survey, supplemented with Subaru/SuprimeCam high-quality imaging in BVRIz-bands, which yields 1916 cluster members (50% of them spectroscopically confirmed) down to a stellar mass M⋆ = 108.6 M⊙. We determine the stellar mass function of these galaxies in different regions of the cluster, by separating the sample into star-forming and passive cluster members. We then determine the intra-cluster light and its properties. We also derive the orbits of low- (M⋆ ≤ 1010.0 M⊙) and high-mass (M⋆ > 1010.0 M⊙) passive galaxies and study the effect of the environment on the mass-size relation of early-type galaxies, selected according to their Sérsic index; the effects are studied separately for the galaxies in each mass range. Finally, we compare the cluster stellar mass density profile with the number density and total-mass density profiles. Results: The stellar mass function of the star-forming cluster galaxies does not depend on the environment. The slope found for passive galaxies becomes flatter in the densest cluster region, which implies that the low-mass component starts to dominate when moving away from the cluster center. The color distribution of the intra-cluster light is consistent with the color of passive cluster members. The analysis of the dynamical orbits of passive galaxies shows that low-mass galaxies have tangential orbits, avoiding small pericenters around the BCG. The

  4. THE TYPE Ia SUPERNOVA RATE IN REDSHIFT 0.5-0.9 GALAXY CLUSTERS

    SciTech Connect

    Sharon, Keren; Gal-Yam, Avishay; Maoz, Dan; Filippenko, Alexei V.; Foley, Ryan J.; Silverman, Jeffrey M.; Ebeling, Harald; Ma Chengjiun; Ofek, Eran O.; Ellis, Richard S.; Kneib, Jean-Paul; Donahue, Megan; Mulchaey, John S.; Voit, G. Mark; Freedman, Wendy L.; Kirshner, Robert P.; Sarajedini, Vicki L.

    2010-08-01

    Supernova (SN) rates are potentially powerful diagnostics of metal enrichment and SN physics, particularly in galaxy clusters with their deep, metal-retaining potentials and relatively simple star formation histories. We have carried out a survey for SNe in galaxy clusters, at a redshift range of 0.5 < z < 0.9, using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. We reimaged a sample of 15 clusters that were previously imaged by ACS, thus obtaining two to three epochs per cluster in which we discovered five likely cluster SNe, six possible cluster Type Ia supernovae, two hostless SN candidates, and several background and foreground events. Keck spectra of the host galaxies were obtained to establish cluster membership. We conducted detailed efficiency simulations, and measured the stellar luminosities of the clusters using Subaru images. We derive a cluster SN rate of 0.35SNu {sub B} {sup +0.17} {sub -0.12}(statistical) {+-}0.13(classification) {+-}0.01(systematic) (where SNu {sub B} = SNe (100 yr 10{sup 10} L {sub B,sun}){sup -1}) and 0.112SNu {sub M} {sup +0.055} {sub -0.039}(statistical) {+-}0.042(classification) {+-}0.005(systematic) (where SNu {sub M} = SNe (100 yr 10{sup 10} M {sub sun}){sup -1}). As in previous measurements of cluster SN rates, the uncertainties are dominated by small-number statistics. The SN rate in this redshift bin is consistent with the SN rate in clusters at lower redshifts (to within the uncertainties), and shows that there is, at most, only a slight increase of cluster SN rate with increasing redshift. The low and fairly constant SN Ia rate out to z {approx} 1 implies that the bulk of the iron mass in clusters was already in place by z {approx} 1. The recently observed doubling of iron abundances in the intracluster medium between z = 1 and 0, if real, is likely to be the result of redistribution of existing iron, rather than new production of iron.

  5. The jet feedback mechanism (JFM): From supernovae to clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Soker, N.; Akashi, M.; Gilkis, A.; Hillel, S.; Papish, O.; Refaelovich, M.; Tsebrenko, D.

    2013-04-01

    We study the similarities of jet-medium interactions in several quite different astrophysical systems using 2D and 3D hydrodynamical numerical simulations, and find many similarities. The systems include cooling flow (CF) clusters of galaxies, core collapse supernovae (CCSNe), planetary nebulae (PNe), and common envelope (CE) evolution. The similarities include hot bubbles inflated by jets in a bipolar structure, vortices on the sides of the jets, vortices inside the inflated bubbles, fragmentation of bubbles to two and more bubbles, and buoyancy of bubbles. The activity in many cases is regulated by a negative feedback mechanism. In CF clusters we find that heating of the intra-cluster medium (ICM) is done by mixing hot shocked jet gas with the ICM, and not by shocks. Our results strengthen the jet feedback mechanism (JFM) as a common process in many astrophysical objects.

  6. Documentation for the machine-readable version of a table of Redshifts for Abell clusters (Sarazin, Rood and Struble 1982)

    NASA Technical Reports Server (NTRS)

    Warren, W. H., Jr.

    1983-01-01

    The machine readable catalog is described. The machine version contains the same data as the published table, which includes a second file with the notes. The computerized data files are prepared at the Astronomical Data Center. Detected discrepancies and cluster identifications based on photometric estimators are included.

  7. The nearby Abell clusters. II - Luminosity and spatial distribution of galaxies in A2175, A2256, and A2384

    NASA Astrophysics Data System (ADS)

    Oegerle, William R.; Jewison, Michael S.; Hoessel, John G.

    1987-03-01

    A study of the luminosity functions and spatial distributions of galaxies in the clusters A2175, A2256, and A2384 has been carried out, based on data obtained at the Palomar 1.2 m Schmidt and 1.5 m telescopes. The authors have also investigated in detail the accuracy of an automated star/galaxy classifier, by comparing the results obtained from the Schmidt plates of A2175 and A2384 with higher-spatial-resolution results from the 1.5 m telescope. Fits of Schechter functions to the luminosity functions of A2384 and A2256 yield values of Mr* ≡ -22, which is in good agreement with the "universal" value of Mr*. However, for these two clusters, slopes of the faint ends of the luminosity functions are distinctly flatter than the canonical value of α = -1.25. The best fit to the luminosity function of A2175 indicates a fairly steep faint end (α = -1.60). The spatial distributions of galaxies in these three clusters are well described by power laws, with no evidence for constant-density cores. These results, taken together with those reported by Beers and Tonry (1986), indicate a strong correlation between the density distribution of galaxies and the presence of a dominant D or cD galaxy in the cluster.

  8. Supernova enrichment of planetary systems in low-mass star clusters

    NASA Astrophysics Data System (ADS)

    Nicholson, Rhana B.; Parker, Richard J.

    2017-02-01

    The presence and abundance of short-lived radioisotopes 26Al and 60Fe in chondritic meteorites implies that the Sun formed in the vicinity of one or more massive stars that exploded as supernovae (SNe). Massive stars are more likely to form in massive star clusters (>1000 M⊙) than lower mass clusters. However, photoevaporation of protoplanetary discs from massive stars and dynamical interactions with passing stars can inhibit planet formation in clusters with radii of ˜1 pc. We investigate whether low-mass (50-200 M⊙) star clusters containing one or two massive stars are a more likely avenue for early Solar system enrichment as they are more dynamically quiescent. We analyse N-body simulations of the evolution of these low-mass clusters and find that a similar fraction of stars experience SN enrichment than in high-mass clusters, despite their lower densities. This is due to two-body relaxation, which causes a significant expansion before the first SN even in clusters with relatively low (100 stars pc-3) initial densities. However, because of the high number of low-mass clusters containing one or two massive stars, the absolute number of enriched stars is the same, if not higher than for more populous clusters. Our results show that direct enrichment of protoplanetary discs from SNe occurs as frequently in low-mass clusters containing one or two massive stars (>20 M⊙) as in more populous star clusters (1000 M⊙). This relaxes the constraints on the direct enrichment scenario and therefore the birth environment of the Solar system.

  9. New dark energy constraints from supernovae, microwave background, and galaxy clustering.

    PubMed

    Wang, Yun; Tegmark, Max

    2004-06-18

    Using supernova, cosmic microwave background, and galaxy clustering data, we make the most accurate measurements to date of the dark energy density rho(X) as a function of cosmic time, constraining it in a rather model-independent way, assuming a flat universe. We find that Einstein's simplest scenario, where rho(X)(z) is constant, remains consistent with these new tight constraints and that a big crunch or big rip is more than 50 Gyr away for a broader class of models allowing such cataclysmic events. We discuss popular pitfalls and hidden priors.

  10. On Iron Enrichment, Star Formation, and Type Ia Supernovae in Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Loewenstein, Michael

    2006-01-01

    The nature of star formation and Type Ia supernovae (SNIa) in galaxies in the field and in rich galaxy clusters are contrasted by juxtaposing the buildup of heavy metals in the universe inferred from observed star formation and supernovae rate histories with data on the evolution of Fe abundances in the intracluster medium (ICM). Models for the chemical evolution of Fe in these environments are constructed, subject to observational constraints, for this purpose. While models with a mean delay for SNIa of 3 Gyr and standard initial mass function (IMF) are fully consistent with observations in the field, cluster Fe enrichment immediately tracked a rapid, top-heavy phase of star formation - although transport of Fe into the ICM may have been more prolonged and star formation likely continued beyond redshift 1. The means of this prompt enrichment consisted of SNII yielding greater than or equal to 0.1 solar mass per explosion (if the SNIa rate normalization is scaled down from its value in the field according to the relative number of candidate progenitor stars in the 3 - 8 solar mass range) and/or SNIa with short delay times originating during the rapid star formation epoch. Star formation is greater than 3 times more efficient in rich clusters than in the field, mitigating the overcooling problem in numerical cluster simulations. Both the fraction of baryons cycled through stars, and the fraction of the total present-day stellar mass in the form of stellar remnants, are substantially greater in clusters than in the field.

  11. Are superluminous supernovae and long GRBs the products of dynamical processes in young dense star clusters?

    SciTech Connect

    Van den Heuvel, E. P. J.; Portegies Zwart, S. F.

    2013-12-20

    Superluminous supernovae (SLSNe) occur almost exclusively in small galaxies (Small/Large Magellanic Cloud (SMC/LMC)-like or smaller), and the few SLSNe observed in larger star-forming galaxies always occur close to the nuclei of their hosts. Another type of peculiar and highly energetic supernovae are the broad-line Type Ic SNe (SN Ic-BL) that are associated with long-duration gamma-ray bursts (LGRBs). Also these have a strong preference for occurring in small (SMC/LMC-like or smaller) star-forming galaxies, and in these galaxies LGRBs always occur in the brightest spots. Studies of nearby star-forming galaxies that are similar to the hosts of LGRBs show that these brightest spots are giant H II regions produced by massive dense young star clusters with many hundreds of O- and Wolf-Rayet-type stars. Such dense young clusters are also found in abundance within a few hundred parsecs from the nucleus of larger galaxies like our own. We argue that the SLSNe and the SNe Ic-BL/LGRBs are exclusive products of two types of dynamical interactions in dense young star clusters. In our model the high angular momentum of the collapsing stellar cores required for the engines of an SN Ic-BL results from the post-main-sequence mergers of dynamically produced cluster binaries with almost equal-mass components. The merger produces a critically rotating single helium star with sufficient angular momentum to produce an LGRB; the observed 'metal aversion' of LGRBs is a natural consequence of the model. We argue that, on the other hand, SLSNe could be the products of runaway multiple collisions in dense clusters, and we present (and quantize) plausible scenarios of how the different types of SLSNe can be produced.

  12. EVIDENCE FOR ENRICHMENT BY SUPERNOVAE IN THE GLOBULAR CLUSTER NGC 6273

    SciTech Connect

    Han, Sang-Il; Lim, Dongwook; Seo, Hyunju; Lee, Young-Wook

    2015-11-10

    In our recent investigation, we showed that narrowband photometry can be combined with low-resolution spectroscopy to effectively search for globular clusters (GCs) with supernova (SN) enrichments. Here we apply this technique to the metal-poor bulge GC NGC 6273 and find that the red giant branch stars in this GC are clearly divided into two distinct subpopulations with different calcium abundances. The Ca rich subpopulation in this GC is also enhanced in CN and CH, showing a positive correlation between them. This trend is identical to the result we found in M22, suggesting that this might be a ubiquitous nature of GCs more strongly affected by SNe in their chemical evolution. Our results suggest that NGC 6273 was massive enough to retain SN ejecta, which would place this cluster in the growing group of GCs with Galactic building block characteristics, such as ω Centauri and Terzan 5.

  13. MUSE integral-field spectroscopy towards the Frontier Fields cluster Abell S1063. II. Properties of low luminosity Lyman α emitters at z > 3

    NASA Astrophysics Data System (ADS)

    Karman, W.; Caputi, K. I.; Caminha, G. B.; Gronke, M.; Grillo, C.; Balestra, I.; Rosati, P.; Vanzella, E.; Coe, D.; Dijkstra, M.; Koekemoer, A. M.; McLeod, D.; Mercurio, A.; Nonino, M.

    2017-02-01

    In spite of their conjectured importance for the Epoch of Reionization, the properties of low-mass galaxies are currently still very much under debate. In this article, we study the stellar and gaseous properties of faint, low-mass galaxies at z > 3. We observed the Frontier Fields cluster Abell S1063 with MUSE over a 2 arcmin2 field, and combined integral-field spectroscopy with gravitational lensing to perform a blind search for intrinsically faint Lyα emitters (LAEs). We determined in total the redshift of 172 galaxies of which 14 are lensed LAEs at z = 3-6.1. We increased the number of spectroscopically-confirmed multiple-image families from 6 to 17 and updated our gravitational-lensing model accordingly. The lensing-corrected Lyα luminosities are with LLyα ≲ 1041.5 erg/s among the lowest for spectroscopically confirmed LAEs at any redshift. We used expanding gaseous shell models to fit the Lyα line profile, and find low column densities and expansion velocities. This is, to our knowledge, the first time that gaseous properties of such faint galaxies at z ≳ 3 are reported. We performed SED modelling to broadband photometry from the U band through the infrared to determine the stellar properties of these LAEs. The stellar masses are very low (106-8M⊙ ), and are accompanied by very young ages of 1-100 Myr. The very high specific star-formation rates ( 100 Gyr-1) are characteristic of starburst galaxies, and we find that most galaxies will double their stellar mass in ≲20 Myr. The UV-continuum slopes β are low in our sample, with β < -2 for all galaxies with M⋆ < 108M⊙. We conclude that our low-mass galaxies at 3 < z < 6 are forming stars at higher rates when correcting for stellar mass effects than seen locally or in more massive galaxies. The young stellar populations with high star-formation rates and low H i column densities lead to continuum slopes and LyC-escape fractions expected for a scenario where low mass galaxies reionise the Universe.

  14. The Type Ia Supernova Rate in Redshift 0.5-0.9 Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Sharon, Keren; Gal-Yam, Avishay; Maoz, Dan; Filippenko, Alexei V.; Foley, Ryan J.; Silverman, Jeffrey M.; Ebeling, Harald; Ma, Cheng-Jiun; Ofek, Eran O.; Kneib, Jean-Paul; Donahue, Megan; Ellis, Richard S.; Freedman, Wendy L.; Kirshner, Robert P.; Mulchaey, John S.; Sarajedini, Vicki L.; Voit, G. Mark

    2010-08-01

    Supernova (SN) rates are potentially powerful diagnostics of metal enrichment and SN physics, particularly in galaxy clusters with their deep, metal-retaining potentials and relatively simple star formation histories. We have carried out a survey for SNe in galaxy clusters, at a redshift range of 0.5 < z < 0.9, using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. We reimaged a sample of 15 clusters that were previously imaged by ACS, thus obtaining two to three epochs per cluster in which we discovered five likely cluster SNe, six possible cluster Type Ia supernovae, two hostless SN candidates, and several background and foreground events. Keck spectra of the host galaxies were obtained to establish cluster membership. We conducted detailed efficiency simulations, and measured the stellar luminosities of the clusters using Subaru images. We derive a cluster SN rate of 0.35SNu B +0.17 -0.12(statistical) ±0.13(classification) ±0.01(systematic) (where SNu B = SNe (100 yr 1010 L B,sun)-1) and 0.112SNu M +0.055 -0.039(statistical) ±0.042(classification) ±0.005(systematic) (where SNu M = SNe (100 yr 1010 M sun)-1). As in previous measurements of cluster SN rates, the uncertainties are dominated by small-number statistics. The SN rate in this redshift bin is consistent with the SN rate in clusters at lower redshifts (to within the uncertainties), and shows that there is, at most, only a slight increase of cluster SN rate with increasing redshift. The low and fairly constant SN Ia rate out to z ≈ 1 implies that the bulk of the iron mass in clusters was already in place by z ≈ 1. The recently observed doubling of iron abundances in the intracluster medium between z = 1 and 0, if real, is likely to be the result of redistribution of existing iron, rather than new production of iron. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of

  15. A New Method to Constrain Supernova Fractions Using X-ray Observations of Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    Bulbul, Esra; Smith, Randall K.; Loewenstein, Michael

    2012-01-01

    Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model called snapec. snapec utilizes a single-temperature thermal plasma code (apec) to model the spectral emission based on metal abundances calculated using the latest SN yields from SN Ia and SN cc explosion models. This approach provides a self-consistent single set of uncertainties on the total number of SN explosions and relative fraction of SN types in the ICM over the cluster lifetime by directly allowing these parameters to be determined by SN yields provided by simulations. We apply our approach to XMM-Newton European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS), and 200 ks simulated Astro-H observations of a cooling flow cluster, A3112.We find that various sets of SN yields present in the literature produce an acceptable fit to the EPIC and RGS spectra of A3112. We infer that 30.3% plus or minus 5.4% to 37.1% plus or minus 7.1% of the total SN explosions are SNe Ia, and the total number of SN explosions required to create the observed metals is in the range of (1.06 plus or minus 0.34) x 10(exp 9), to (1.28 plus or minus 0.43) x 10(exp 9), fromsnapec fits to RGS spectra. These values may be compared to the enrichment expected based on well-established empirically measured SN rates per star formed. The proportions of SNe Ia and SNe cc inferred to have enriched the ICM in the inner 52 kiloparsecs of A3112 is consistent with these specific rates, if one applies a correction for the metals locked up in stars. At the same time, the inferred level of SN enrichment corresponds to a star-to-gas mass ratio that is several times greater than the 10% estimated globally for clusters in the A3112 mass range.

  16. A NEW METHOD TO CONSTRAIN SUPERNOVA FRACTIONS USING X-RAY OBSERVATIONS OF CLUSTERS OF GALAXIES

    SciTech Connect

    Bulbul, Esra; Smith, Randall K.; Loewenstein, Michael

    2012-07-01

    Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model called snapec. snapec utilizes a single-temperature thermal plasma code (apec) to model the spectral emission based on metal abundances calculated using the latest SN yields from SN Ia and SN cc explosion models. This approach provides a self-consistent single set of uncertainties on the total number of SN explosions and relative fraction of SN types in the ICM over the cluster lifetime by directly allowing these parameters to be determined by SN yields provided by simulations. We apply our approach to XMM-Newton European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS), and 200 ks simulated Astro-H observations of a cooling flow cluster, A3112. We find that various sets of SN yields present in the literature produce an acceptable fit to the EPIC and RGS spectra of A3112. We infer that 30.3% {+-} 5.4% to 37.1% {+-} 7.1% of the total SN explosions are SNe Ia, and the total number of SN explosions required to create the observed metals is in the range of (1.06 {+-} 0.34) Multiplication-Sign 10{sup 9} to (1.28 {+-} 0.43) Multiplication-Sign 10{sup 9}, from snapec fits to RGS spectra. These values may be compared to the enrichment expected based on well-established empirically measured SN rates per star formed. The proportions of SNe Ia and SNe cc inferred to have enriched the ICM in the inner 52 kpc of A3112 is consistent with these specific rates, if one applies a correction for the metals locked up in stars. At the same time, the inferred level of SN enrichment corresponds to a star-to-gas mass ratio that is several times greater than the 10% estimated globally for clusters in the A3112 mass range.

  17. Radioactive Probes of the Supernova-contaminated Solar Nebula: Evidence that the Sun Was Born in a Cluster

    NASA Astrophysics Data System (ADS)

    Looney, Leslie W.; Tobin, John J.; Fields, Brian D.

    2006-12-01

    We construct a simple model for radioisotopic enrichment of the protosolar nebula by injection from a nearby supernova, based on the inverse square law for ejecta dispersion. In this parameter study, the presolar radioisotopic abundances (i.e., in solar masses) demand a nearby supernova: its distance D can be no larger than 66 times the radius of the protosolar nebula, at a 90% confidence level, assuming 1 Msolar of protosolar material. The relevant size of the nebula depends on its state of evolution at the time of radioactivity injection. In one scenario, a collection of low-mass stars, including our Sun, formed in a group or cluster with a high-mass star that ended its life as a supernova while our Sun was still a protostar, a starless core, or perhaps a diffuse cloud. Using recent observations of protostars to estimate the size of the protosolar nebula constrains the distance of the supernova to D~0.02-1.6 pc. This supernova distance limit is consistent with the scales of low-mass star formation around one or more massive stars, but it is closer than expected were the Sun formed in an isolated, solitary state. Consequently, if any presolar radioactivities originated via supernova injection, we must conclude that our Sun was a member of such a group or cluster that has since dispersed; thus, solar system formation should be understood in this context. The temporal choreography from supernova ejecta to meteorites is important, as the modeled timescale is <=1.8 Myr. Finally, the model does not distinguish between progenitor masses from 15 to 25 Msolar, although the 20 Msolar model is somewhat preferred.

  18. The Abell 85 BCG: A Nucleated, Coreless Galaxy

    NASA Astrophysics Data System (ADS)

    Madrid, Juan P.; Donzelli, Carlos J.

    2016-03-01

    New high-resolution r-band imaging of the brightest cluster galaxy (BCG) in Abell 85 (Holm 15A) was obtained using the Gemini Multi Object Spectrograph. These data were taken with the aim of deriving an accurate surface brightness profile of the BCG of Abell 85, in particular, its central region. The new Gemini data show clear evidence of a previously unreported nuclear emission that is evident as a distinct light excess in the central kiloparsec of the surface brightness profile. We find that the light profile is never flat nor does it present a downward trend toward the center of the galaxy. That is, the new Gemini data show a different physical reality from the featureless, “evacuated core” recently claimed for the Abell 85 BCG. After trying different models, we find that the surface brightness profile of the BCG of Abell 85 is best fit by a double Sérsic model.

  19. THE ABELL 85 BCG: A NUCLEATED, CORELESS GALAXY

    SciTech Connect

    Madrid, Juan P.

    2016-03-01

    New high-resolution r-band imaging of the brightest cluster galaxy (BCG) in Abell 85 (Holm 15A) was obtained using the Gemini Multi Object Spectrograph. These data were taken with the aim of deriving an accurate surface brightness profile of the BCG of Abell 85, in particular, its central region. The new Gemini data show clear evidence of a previously unreported nuclear emission that is evident as a distinct light excess in the central kiloparsec of the surface brightness profile. We find that the light profile is never flat nor does it present a downward trend toward the center of the galaxy. That is, the new Gemini data show a different physical reality from the featureless, “evacuated core” recently claimed for the Abell 85 BCG. After trying different models, we find that the surface brightness profile of the BCG of Abell 85 is best fit by a double Sérsic model.

  20. A Strong Merger Shock in Abell 665

    NASA Technical Reports Server (NTRS)

    Dasadia, S.; Sun, M.; Sarazin, C.; Morandi, A.; Markevitch, M.; Wik, D.; Feretti, L.; Giovannini, G.; Govoni, F.

    2016-01-01

    Deep (103 ks) Chandra observations of Abell 665 have revealed rich structures in this merging galaxy cluster, including a strong shock and two cold fronts. The newly discovered shock has a Mach number of M =?3.0 +/- 0.6, propagating in front of a cold disrupted cloud. This makes Abell 665 the second cluster, after the Bullet cluster, where a strong merger shock of M is approximately 3 has been detected. The shock velocity from jump conditions is consistent with (2.7 +/- 0.7) × 10(exp 3) km s(exp -1). The new data also reveal a prominent southern cold front with potentially heated gas ahead of it. Abell 665 also hosts a giant radio halo. There is a hint of diffuse radio emission extending to the shock at the north, which needs to be examined with better radio data. This new strong shock provides a great opportunity to study the reacceleration model with the X-ray and radio data combined.

  1. New Type Continuities via Abel Convergence

    PubMed Central

    Albayrak, Mehmet

    2014-01-01

    We investigate the concept of Abel continuity. A function f defined on a subset of ℝ, the set of real numbers, is Abel continuous if it preserves Abel convergent sequences. Some other types of continuities are also studied and interesting result is obtained. It turned out that uniform limit of a sequence of Abel continuous functions is Abel continuous and the set of Abel continuous functions is a closed subset of continuous functions. PMID:24883393

  2. Hα photometry of Abell 2390

    NASA Astrophysics Data System (ADS)

    Balogh, Michael L.; Morris, Simon L.

    2000-11-01

    We present the results of a search for strong Hα emission line galaxies (rest frame equivalent widths greater than 50Å) in the z~0.23 cluster Abell 2390. The survey contains 1189galaxies over 270arcmin2, and is 50per cent complete at Mr~-17.5+5logh. The fraction of galaxies in which Hα is detected at the 2σ level rises from 0.0 in the central regions (excluding the cD galaxy) to 12.5+/-8per cent at R200. For 165 of the galaxies in our catalogue, we compare the Hα equivalent widths with their [Oii] λ3727 equivalent widths, from the Canadian Network for Observational Cosmology (CNOC1) spectra. The fraction of strong Hα emission line galaxies is consistent with the fraction of strong [Oii] emission galaxies in the CNOC1 sample: only 2+/-1per cent have no detectable [Oii] emission and yet significant (>2σ) Hα equivalent widths. Dust obscuration, non-thermal ionization, and aperture effects are all likely to contribute to this non-correspondence of emission lines. We identify six spectroscopically `secure' k+a galaxies [W0(Oii)<5Å and W0(Hδ)>~5Å] at least two of these show strong signs in Hα of star formation in regions that are covered by the slit from which the spectra were obtained. Thus, some fraction of galaxies classified as k+a based on spectra shortward of 6000Å are likely to be undergoing significant star formation. These results are consistent with a `strangulation' model for cluster galaxy evolution, in which star formation in cluster galaxies is gradually decreased, and is neither enhanced nor abruptly terminated by the cluster environment.

  3. A Multiply-Imaged z ˜ 6.3 Lyman Alpha Emitter candidate behind Abell 2261

    NASA Astrophysics Data System (ADS)

    Rydberg, Claes-Erik; Zitrin, Adi; Zackrisson, Erik; Melinder, Jens; Whalen, Daniel J.; Klessen, Ralf S.; Gonzalez, Juan; Östlin, Göran; Carollo, Daniela

    2017-01-01

    While the Lyman-α (Lyα) emission line serves as an important tool in the study of galaxies at z ≲ 6, finding Lyα emitters (LAE) at significantly higher redshifts has been more challenging, probably because of the increasing neutrality of the intergalactic medium above z ˜ 6. Galaxies with extremely high rest-frame Lyα equivalent widths, EW(Lyα) ≳ 150 Å, at z > 6 are good candidates for Lyα follow-up observations, and can stand out in multiband imaging surveys because of their unusual colors. We have conducted a photometric search for such objects in the Cluster Lensing And Supernova survey with Hubble (CLASH), and report here the identification of three likely gravitationally-lensed images of a single LAE candidate at z ˜ 6.3, behind the galaxy cluster Abell 2261 (z = 0.225). In the process, we also measured with Keck/MOSFIRE the first spectroscopic redshift of a multiply-imaged galaxy behind Abell 2261, at z = 3.337. This allows us to calibrate the lensing model, which in turn is used to study the properties of the candidate LAE. Population III galaxy spectral energy distribution (SED) model fits to the CLASH broadband photometry of the possible LAE provide a slightly better fit than Population I/II models. The best fitted model suggests intrinsic EW(Lyα) ≈160 Å after absorption in the interstellar and intergalactic medium. Future spectroscopic observations will examine this prediction as well as shed more light on the morphology of this object, which indicates it may be a merger of two smaller galaxies.

  4. Galaxy clustering, CMB and supernova data constraints on ϕCDM model with massive neutrinos

    NASA Astrophysics Data System (ADS)

    Chen, Yun; Xu, Lixin

    2016-01-01

    We investigate a scalar field dark energy model (i.e., ϕCDM model) with massive neutrinos, where the scalar field possesses an inverse power-law potential, i.e., V (ϕ) ∝ϕ-α (α > 0). We find that the sum of neutrino masses Σmν has significant impacts on the CMB temperature power spectrum and on the matter power spectrum. In addition, the parameter α also has slight impacts on the spectra. A joint sample, including CMB data from Planck 2013 and WMAP9, galaxy clustering data from WiggleZ and BOSS DR11, and JLA compilation of Type Ia supernova observations, is adopted to confine the parameters. Within the context of the ϕCDM model under consideration, the joint sample determines the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the Thomson scattering optical depth due to reionization, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ* = (1.0415-0.0011+0.0012) ×10-2, τ =0.0914-0.0242+0.0266, Ωbh2 = 0.0222 ± 0.0005, Ωch2 = 0.1177 ± 0.0036, and ns =0.9644-0.0119+0.0118, respectively, at 95% confidence level (CL). It turns out that α < 4.995 at 95% CL for the ϕCDM model. And yet, the ΛCDM scenario corresponding to α = 0 is not ruled out at 95% CL. Moreover, we get Σmν < 0.262 eV at 95% CL for the ϕCDM model, while the corresponding one for the ΛCDM model is Σmν < 0.293 eV. The allowed scale of Σmν in the ϕCDM model is a bit smaller than that in the ΛCDM model. It is consistent with the qualitative analysis, which reveals that the increases of α and Σmν both can result in the suppression of the matter power spectrum. As a consequence, when α is larger, in order to avoid suppressing the matter power spectrum too much, the value of Σmν should be smaller.

  5. Origin of central abundances in the hot intra-cluster medium. II. Chemical enrichment and supernova yield models

    NASA Astrophysics Data System (ADS)

    Mernier, F.; de Plaa, J.; Pinto, C.; Kaastra, J. S.; Kosec, P.; Zhang, Y.-Y.; Mao, J.; Werner, N.; Pols, O. R.; Vink, J.

    2016-11-01

    The hot intra-cluster medium (ICM) is rich in metals, which are synthesised by supernovae (SNe) and accumulate over time into the deep gravitational potential well of clusters of galaxies. Since most of the elements visible in X-rays are formed by type Ia (SNIa) and/or core-collapse (SNcc) supernovae, measuring their abundances gives us direct information on the nucleosynthesis products of billions of SNe since the epoch of the star formation peak (z 2-3). In this study, we compare the most accurate average X/Fe abundance ratios (compiled in a previous work from XMM-Newton EPIC and RGS observations of 44 galaxy clusters, groups, and ellipticals), representative of the chemical enrichment in the nearby ICM, to various SNIa and SNcc nucleosynthesis models found in the literature. The use of a SNcc model combined to any favoured standard SNIa model (deflagration or delayed-detonation) fails to reproduce our abundance pattern. In particular, the Ca/Fe and Ni/Fe ratios are significantly underestimated by the models. We show that the Ca/Fe ratio can be reproduced better, either by taking a SNIa delayed-detonation model that matches the observations of the Tycho supernova remnant, or by adding a contribution from the "Ca-rich gap transient" SNe, whose material should easily mix into the hot ICM. On the other hand, the Ni/Fe ratio can be reproduced better by assuming that both deflagration and delayed-detonation SNIa contribute in similar proportions to the ICM enrichment. In either case, the fraction of SNIa over the total number of SNe (SNIa+SNcc) contributing to the ICM enrichment ranges within 29-45%. This fraction is found to be systematically higher than the corresponding SNIa/(SNIa+SNcc) fraction contributing to the enrichment of the proto-solar environnement (15-25%). We also discuss and quantify two useful constraints on both SNIa (i.e. the initial metallicity on SNIa progenitors and the fraction of low-mass stars that result in SNIa) and SNcc (i.e. the effect of

  6. Bubbles and B-Flats: A Deep Observation of Abell 2052

    NASA Astrophysics Data System (ADS)

    Blanton, Elizabeth

    2004-09-01

    The cooling flow cluster Abell 2052 has, arguably, the morphology most similar to the Perseus cluster as seen with Chandra images. Two clear bubbles to the N and S of the center of Abell 2052 are filled with the radio lobes associated with 3C 317. An unsharp-masked image reveals faint ripple features similar to those seen in the Perseus cluster which may represent the propagation of sound waves into the cluster from the radio source. We propose to observe Abell 2052 much more deeply to study the ripple features, search for ghost bubbles, search for cooling gas in the bright shells around the radio source that may link the X-ray and H-alpha emission, detect hot gas within the X-ray holes, and directly compare the star formation and cooling rates in the cluster center.

  7. SPITZER OBSERVATIONS OF ABELL 1763. I. INFRARED AND OPTICAL PHOTOMETRY

    SciTech Connect

    Edwards, Louise O. V.; Fadda, Dario; Biviano, Andrea

    2010-02-15

    We present a photometric analysis of the galaxy cluster Abell 1763 at visible and infrared wavelengths. Included are fully reduced images in r', J, H, and K{sub s} obtained using the Palomar 200in telescope, as well as the IRAC and MIPS images from Spitzer. The cluster is covered out to approximately 3 virial radii with deep 24 {mu}m imaging (a 5{sigma} depth of 0.2 mJy). This same field of {approx}40' x 40' is covered in all four IRAC bands as well as the longer wavelength MIPS bands (70 and 160 {mu}m). The r' imaging covers {approx}0.8 deg{sup 2} down to 25.5 mag, and overlaps with most of the MIPS field of view. The J, H, and K{sub s} images cover the cluster core and roughly half of the filament galaxies, which extend toward the neighboring cluster, Abell 1770. This first, in a series of papers on Abell 1763, discusses the data reduction methods and source extraction techniques used for each data set. We present catalogs of infrared sources (with 24 and/or 70 {mu}m emission) and their corresponding emission in the optical (u', g', r', i', z'), and near- to far-IR (J, H, K{sub s} , IRAC, and MIPS 160 {mu}m). We provide the catalogs and reduced images to the community through the NASA/IPAC Infrared Science Archive.

  8. The Young, Massive, Star Cluster Sandage-96 After the Explosion of Supernova 2004dj in NGC 2403

    NASA Astrophysics Data System (ADS)

    Vinkó, J.; Sárneczky, K.; Balog, Z.; Immler, S.; Sugerman, B. E. K.; Brown, P. J.; Misselt, K.; Szabó, Gy. M.; Csizmadia, Sz.; Kun, M.; Klagyivik, P.; Foley, R. J.; Filippenko, A. V.; Csák, B.; Kiss, L. L.

    2009-04-01

    The bright Type II-plateau supernova (SN) 2004dj occurred within the young, massive stellar cluster Sandage-96 in a spiral arm of NGC 2403. New multiwavelength observations obtained with several ground-based and space-based telescopes were combined to study the radiation from Sandage-96 after SN 2004dj faded away. Sandage-96 started to dominate the flux in the optical bands starting from 2006 September (~800 days after explosion). The optical fluxes are equal to the pre-explosion ones within the observational uncertainties. An optical Keck spectrum obtained ~900 days after explosion shows the dominant blue continuum from the cluster stars shortward of 6000 Å as well as strong SN nebular emission lines redward. The integrated spectral energy distribution (SED) of the cluster has been extended into the ultraviolet region by archival XMM-Newton and new Swift observations, and compared with theoretical models. The outer parts of the cluster have been resolved by the Hubble Space Telescope, allowing the construction of a color-magnitude diagram (CMD). The fitting of the cluster SED with theoretical isochrones results in cluster ages distributed between 10 and 40 Myr, depending on the assumed metallicity and the theoretical model family. The isochrone fitting of the CMDs indicates that the resolved part of the cluster consists of stars having a bimodal age distribution: a younger population at ~10-16 Myr and an older one at ~32-100 Myr. The older population has an age distribution similar to that of the other nearby field stars. This may be explained with the hypothesis that the outskirts of Sandage-96 are contaminated by stars captured from the field during cluster formation. The young age of Sandage-96 and the comparison of its pre and postexplosion SEDs suggest 12 lsim M prog lsim 20 M sun as the most probable mass range for the progenitor of SN 2004dj. This is consistent with, but perhaps slightly higher than, most of the other Type II-plateau SN progenitor masses

  9. Cool Core Disruption in Abell 1763

    NASA Astrophysics Data System (ADS)

    Douglass, Edmund; Blanton, Elizabeth L.; Clarke, Tracy E.; Randall, Scott W.; Edwards, Louise O. V.; Sabry, Ziad

    2017-01-01

    We present the analysis of a 20 ksec Chandra archival observation of the massive galaxy cluster Abell 1763. A model-subtracted image highlighting excess cluster emission reveals a large spiral structure winding outward from the core to a radius of ~950 kpc. We measure the gas of the inner spiral to have significantly lower entropy than non-spiral regions at the same radius. This is consistent with the structure resulting from merger-induced motion of the cluster’s cool core, a phenomenon seen in many systems. Atypical of spiral-hosting clusters, an intact cool core is not detected. Its absence suggests the system has experienced significant disruption since the initial dynamical encounter that set the sloshing core in motion. Along the major axis of the elongated ICM distribution we detect thermal features consistent with the merger event most likely responsible for cool core disruption. The merger-induced transition towards non-cool core status will be discussed. The interaction between the powerful (P1.4 ~ 1026 W Hz-1) cluster-center WAT radio source and its ICM environment will also be discussed.

  10. Hierarchical Velocity Structure in the Core of Abell 2597

    NASA Technical Reports Server (NTRS)

    Still, Martin; Mushotzky, Richard

    2004-01-01

    We present XMM-Newton RGS and EPIC data of the putative cooling flow cluster Abell 2597. Velocities of the low-ionization emission lines in the spectrum are blue shifted with respect to the high-ionization lines by 1320 (sup +660) (sub -210) kilometers per second, which is consistent with the difference in the two peaks of the galaxy velocity distribution and may be the signature of bulk turbulence, infall, rotation or damped oscillation in the cluster. A hierarchical velocity structure such as this could be the direct result of galaxy mergers in the cluster core, or the injection of power into the cluster gas from a central engine. The uniform X-ray morphology of the cluster, the absence of fine scale temperature structure and the random distribution of the the galaxy positions, independent of velocity, suggests that our line of sight is close to the direction of motion. These results have strong implications for cooling flow models of the cluster Abell 2597. They give impetus to those models which account for the observed temperature structure of some clusters using mergers instead of cooling flows.

  11. Stellar populations of BCGs, close companions and intracluster light in Abell 85, Abell 2457 and IIZw108

    NASA Astrophysics Data System (ADS)

    Edwards, L. O. V.; Alpert, H. S.; Trierweiler, I. L.; Abraham, T.; Beizer, V. G.

    2016-09-01

    We present the first results from an integral field unit (IFU) spectroscopic survey of a ˜75 kpc region around three brightest cluster galaxies (BCGs), combining over 100 IFU fibres to study the intracluster light (ICL). We fit population synthesis models to estimate age and metallicity. For Abell 85 and Abell 2457, the ICL is best-fit with a fraction of old, metal-rich stars like in the BCG, but requires 30-50 per cent young and metal-poor stars, a component not found in the BCGs. This is consistent with the ICL having been formed by a combination of interactions with less massive, younger, more metal-poor cluster members in addition to stars that form the BCG. We find that the three galaxies are in different stages of evolution and may be the result of different formation mechanisms. The BCG in Abell 85 is near a relatively young, metal-poor galaxy, but the dynamical friction time-scale is long and the two are unlikely to be undergoing a merger. The outer regions of Abell 2457 show a higher relative fraction of metal-poor stars, and we find one companion, with a higher fraction of young, metal-poor stars than the BCG, which is likely to merge within a gigayear. Several luminous red galaxies are found at the centre of the cluster IIZw108, with short merger time-scales, suggesting that the system is about to embark on a series of major mergers to build up a dominant BCG. The young, metal-poor component found in the ICL is not found in the merging galaxies.

  12. The discovery of diffuse steep spectrum sources in Abell 2256

    NASA Astrophysics Data System (ADS)

    van Weeren, R. J.; Intema, H. T.; Oonk, J. B. R.; Röttgering, H. J. A.; Clarke, T. E.

    2009-12-01

    Context: Hierarchical galaxy formation models indicate that during their lifetime galaxy clusters undergo several mergers. An example of such a merging cluster is Abell 2256. Here we report on the discovery of three diffuse radio sources in the periphery of Abell 2256, using the Giant Metrewave Radio Telescope (GMRT). Aims: The aim of the observations was to search for diffuse ultra-steep spectrum radio sources within the galaxy cluster Abell 2256. Methods: We have carried out GMRT 325 MHz radio continuum observations of Abell 2256. V, R and I band images of the cluster were taken with the 4.2 m William Herschel Telescope (WHT). Results: We have discovered three diffuse elongated radio sources located about 1 Mpc from the cluster center. Two are located to the west of the cluster center, and one to the southeast. The sources have a measured physical extent of 170, 140 and 240 kpc, respectively. The two western sources are also visible in deep low-resolution 115-165 MHz Westerbork Synthesis Radio Telescope (WSRT) images, although they are blended into a single source. For the combined emission of the blended source we find an extreme spectral index (α) of -2.05 ± 0.14 between 140 and 351 MHz. The extremely steep spectral index suggests these two sources are most likely the result of adiabatic compression of fossil radio plasma due to merger shocks. For the source to the southeast, we find that {α < -1.45} between 1369 and 325 MHz. We did not find any clear optical counterparts to the radio sources in the WHT images. Conclusions: The discovery of the steep spectrum sources implies the existence of a population of faint diffuse radio sources in (merging) clusters with such steep spectra that they have gone unnoticed in higher frequency (⪆1 GHz) observations. Simply considering the timescales related to the AGN activity, synchrotron losses, and the presence of shocks, we find that most massive clusters should possess similar sources. An exciting possibility

  13. X-Ray Imaging-Spectroscopy of Abell 1835

    NASA Technical Reports Server (NTRS)

    Peterson, J. R.; Paerels, F. B. S.; Kaastra, J. S.; Arnaud, M.; Reiprich T. H.; Fabian, A. C.; Mushotzky, R. F.; Jernigan, J. G.; Sakelliou, I.

    2000-01-01

    We present detailed spatially-resolved spectroscopy results of the observation of Abell 1835 using the European Photon Imaging Cameras (EPIC) and the Reflection Grating Spectrometers (RGS) on the XMM-Newton observatory. Abell 1835 is a luminous (10(exp 46)ergs/s), medium redshift (z = 0.2523), X-ray emitting cluster of galaxies. The observations support the interpretation that large amounts of cool gas are present in a multi-phase medium surrounded by a hot (kT(sub e) = 8.2 keV) outer envelope. We detect O VIII Ly(alpha) and two Fe XXIV complexes in the RGS spectrum. The emission measure of the cool gas below kT(sub e) = 2.7 keV is much lower than expected from standard cooling-flow models, suggesting either a more complicated cooling process than simple isobaric radiative cooling or differential cold absorption of the cooler gas.

  14. THE SUPERNOVA DELAY TIME DISTRIBUTION IN GALAXY CLUSTERS AND IMPLICATIONS FOR TYPE-Ia PROGENITORS AND METAL ENRICHMENT

    SciTech Connect

    Maoz, Dan; Sharon, Keren; Avishay Gal-Yam

    2010-10-20

    Knowledge of the supernova (SN) delay time distribution (DTD)-the SN rate versus time that would follow a hypothetical brief burst of star formation-can shed light on SN progenitors and physics, as well as on the timescales of chemical enrichment in different environments. We compile recent measurements of the Type-Ia SN (SN Ia) rate in galaxy clusters at redshifts from z = 0 out to z = 1.45, just 2 Gyr after cluster star formation at z {approx} 3. We review the plausible range for the observed total iron-to-stellar mass ratio in clusters, based on the latest data and analyses, and use it to constrain the time-integrated number of SN Ia events in clusters. With these data, we recover the DTD of SNe Ia in cluster environments. The DTD is sharply peaked at the shortest time-delay interval we probe, 0Gyr < t < 2.2 Gyr, with a low tail out to delays of {approx}10 Gyr, and is remarkably consistent with several recent DTD reconstructions based on different methods, applied to different environments. We test DTD models from the literature, requiring that they simultaneously reproduce the observed cluster SN rates and the observed iron-to-stellar mass ratios. A parameterized power-law DTD of the form t {sup -1.2{+-}0.3} from t = 400 Myr to a Hubble time can satisfy both constraints. Shallower power laws such as t {sup -1/2} cannot, assuming a single DTD, and a single star formation burst (either brief or extended) at high z. This implies that 50%-85% of SNe Ia explode within 1 Gyr of star formation. DTDs from double-degenerate (DD) models, which generically have {approx}t {sup -1} shapes over a wide range of timescales, match the data, but only if their predictions are scaled up by factors of 5-10. Single-degenerate (SD) DTDs always give poor fits to the data, due to a lack of delayed SNe and overall low numbers of SNe. The observations can also be reproduced with a combination of two SN Ia populations-a prompt SD population of SNe Ia that explodes within a few Gyr of star

  15. LOW-RESOLUTION SPECTROSCOPY FOR THE GLOBULAR CLUSTERS WITH SIGNS OF SUPERNOVA ENRICHMENT: M22, NGC 1851, AND NGC 288

    SciTech Connect

    Lim, Dongwook; Han, Sang-Il; Lee, Young-Wook; Roh, Dong-Goo; Sohn, Young-Jong; Chun, Sang-Hyun; Lee, Jae-Woo; Johnson, Christian I.

    2015-01-01

    There is increasing evidence for the presence of multiple red giant branches (RGBs) in the color-magnitude diagrams of massive globular clusters (GCs). In order to investigate the origin of this split on the RGB, we have performed new narrow-band Ca photometry and low-resolution spectroscopy for M22, NGC 1851, and NGC 288. We find significant differences (more than 4σ) in calcium abundance from the spectroscopic HK' index for M22 and NGC 1851. We also find more than 8σ differences in CN-band strength between the Ca-strong and Ca-weak subpopulations for these GCs. For NGC 288, however, a large difference is detected only in the CN strength. The calcium abundances of RGB stars in this GC are identical to within the errors. This is consistent with the conclusion from our new Ca photometry where the RGB splits are confirmed in M22 and NGC 1851, but not in NGC 288. We also find interesting differences in the CN-CH correlations among these GCs. While CN and CH are anti-correlated in NGC 288, they show a positive correlation in M22. NGC 1851, however, shows no difference in CH between the two groups of stars with different CN strengths. We suggest that all of these systematic differences would be best explained by how strongly Type II supernovae enrichment has contributed to the chemical evolution of these GCs.

  16. A uniform contribution of core-collapse and type Ia supernovae to the chemical enrichment pattern in the outskirts of the Virgo Cluster

    DOE PAGES

    Simionescu, A.; Werner, N.; Urban, O.; ...

    2015-09-24

    We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r200). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metalmore » abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. Furthermore, we estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.« less

  17. A UNIFORM CONTRIBUTION OF CORE-COLLAPSE AND TYPE Ia SUPERNOVAE TO THE CHEMICAL ENRICHMENT PATTERN IN THE OUTSKIRTS OF THE VIRGO CLUSTER

    SciTech Connect

    Simionescu, A.; Ichinohe, Y.; Werner, N.; Urban, O.; Allen, S. W.; Zhuravleva, I.

    2015-10-01

    We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r{sub 200}). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metal abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. We estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.

  18. A uniform contribution of core-collapse and type Ia supernovae to the chemical enrichment pattern in the outskirts of the Virgo Cluster

    SciTech Connect

    Simionescu, A.; Werner, N.; Urban, O.; Allen, S. W.; Ichinohe, Y.; Zhuravleva, I.

    2015-09-24

    We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r200). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metal abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. Furthermore, we estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.

  19. Ram pressure induced star formation in Abell 3266

    NASA Astrophysics Data System (ADS)

    Bonsall, Brittany

    An X-ray observation of the merging galaxy cluster Abell 3266 was obtained via the ROSAT PSPC. This information, along with spectroscopic data from the WIde-field Nearby Galaxy-clusters Survey (i.e. WINGS), were used to investigate whether ram pressure is a mechanism that influences star formation. Galaxies exhibiting ongoing star formation are identified by the presence of strong Balmer lines (Hbeta), known to correspond to early type stars. Older galaxies where a rapid increase in star formation has recently ceased, known as E+A galaxies, are identified by strong Hbeta absorption coupled with little to no [OII] emission. The correlation between recent star formation and "high" ram pressure, as defined by Kapferer et al. (2009) as ≥ 5 x 10-11 dyn cm-2, was tested and lead to a contradiction of the previously held belief that ram pressure influences star formation on the global cluster scale.

  20. SHOCKING TAILS IN THE MAJOR MERGER ABELL 2744

    SciTech Connect

    Owers, Matt S.; Couch, Warrick J.; Nulsen, Paul E. J.; Randall, Scott W.

    2012-05-01

    We identify four rare 'jellyfish' galaxies in Hubble Space Telescope imagery of the major merger cluster Abell 2744. These galaxies harbor trails of star-forming knots and filaments which have formed in situ in gas tails stripped from the parent galaxies, indicating they are in the process of being transformed by the environment. Further evidence for rapid transformation in these galaxies comes from their optical spectra, which reveal starburst, poststarburst, and active galactic nucleus features. Most intriguingly, three of the jellyfish galaxies lie near intracluster medium features associated with a merging 'Bullet-like' subcluster and its shock front detected in Chandra X-ray images. We suggest that the high-pressure merger environment may be responsible for the star formation in the gaseous tails. This provides observational evidence for the rapid transformation of galaxies during the violent core passage phase of a major cluster merger.

  1. Shocking Tails in the Major Merger Abell 2744

    NASA Astrophysics Data System (ADS)

    Owers, Matt S.; Couch, Warrick J.; Nulsen, Paul E. J.; Randall, Scott W.

    2012-05-01

    We identify four rare "jellyfish" galaxies in Hubble Space Telescope imagery of the major merger cluster Abell 2744. These galaxies harbor trails of star-forming knots and filaments which have formed in situ in gas tails stripped from the parent galaxies, indicating they are in the process of being transformed by the environment. Further evidence for rapid transformation in these galaxies comes from their optical spectra, which reveal starburst, poststarburst, and active galactic nucleus features. Most intriguingly, three of the jellyfish galaxies lie near intracluster medium features associated with a merging "Bullet-like" subcluster and its shock front detected in Chandra X-ray images. We suggest that the high-pressure merger environment may be responsible for the star formation in the gaseous tails. This provides observational evidence for the rapid transformation of galaxies during the violent core passage phase of a major cluster merger.

  2. Very old and very young compact objects: X-ray studies of galactic globular clusters and recent core-collapse supernovae

    NASA Astrophysics Data System (ADS)

    Pooley, David Aaron

    2003-09-01

    This thesis comprises the results of two distinct areas of research, namely, X-ray studies of Galactic globular clusters and X-ray studies of recent core collapse supernovae. My analyses of the Chandra X-ray Observatory observations of the globular clusters NGC 6752 and NGC 6440 revealed as many low- luminosity X-ray sources as was in the entire census of globular cluster sources with the previous best X-ray imaging instrument, Röntgensatellit. In the observation of NGC 6752, I detect 6 X-ray sources within the 10''.5 core radius and 13 more within the 115' half-mass radius down to a limiting luminosity of Lx ≈ 1030 ergs s -1 for cluster sources. Based on a reanalysis of archival data from the Hubble Space Telescope and the Australia Telescope Compact Array, I make 12 optical identifications and one radio identification. Based on X- ray and optical properties of the identifications, I find 10 likely cataclysmic variables (CVs), 1 3 likely RS CVn or BY Dra systems, and 1 or 2 possible background objects. Of the 7 sources for which no optical identifications were made, one was detected in the archival radio data, and another was found to be a millisecond pulsar. Of the remaining sources, I expect that ˜2 4 are background objects and that the rest are either CVs or millisecond pulsars whose radio emission has not been detected. These and other Chandra results on globular clusters indicate that the dozens of CVs per cluster expected by theoretical arguments are being found. Based upon X-ray luminosities and colors, I conclude that there are 4 5 likely quiescent low-mass X-ray binaries and that most of the other sources are cataclysmic variables. I compare these results to Chandra results from other globular clusters and find the X-ray luminosity functions differ among the clusters. Observations of the Type II-P (plateau) Supernova (SN) 1999em and Type IIn (narrow emission line) SN 1998S have enabled estimation of the profile of the SN ejecta, the structure of the

  3. LensPerfect Analysis of Abell 1689

    NASA Astrophysics Data System (ADS)

    Coe, Dan A.

    2007-12-01

    I present the first massmap to perfectly reproduce the position of every gravitationally-lensed multiply-imaged galaxy detected to date in ACS images of Abell 1689. This massmap was obtained using a powerful new technique made possible by a recent advance in the field of Mathematics. It is the highest resolution assumption-free Dark Matter massmap to date, with the resolution being limited only by the number of multiple images detected. We detect 8 new multiple image systems and identify multiple knots in individual galaxies to constrain a grand total of 168 knots within 135 multiple images of 42 galaxies. No assumptions are made about mass tracing light, and yet the brightest visible structures in A1689 are reproduced in our massmap, a few with intriguing positional offsets. Our massmap probes radii smaller than that resolvable in current Dark Matter simulations of galaxy clusters. And at these radii, we observe slight deviations from the NFW and Sersic profiles which describe simulated Dark Matter halos so well. While we have demonstrated that our method is able to recover a known input massmap (to limited resolution), further tests are necessary to determine the uncertainties of our mass profile and positions of massive subclumps. I compile the latest weak lensing data from ACS, Subaru, and CFHT, and attempt to fit a single profile, either NFW or Sersic, to both the observed weak and strong lensing. I confirm the finding of most previous authors, that no single profile fits extremely well to both simultaneously. Slight deviations are revealed, with the best fits slightly over-predicting the mass profile at both large and small radius. Our easy-to-use software, called LensPerfect, will be made available soon. This research was supported by the European Commission Marie Curie International Reintegration Grant 017288-BPZ and the PNAYA grant AYA2005-09413-C02.

  4. Tracking star formation in dwarf cluster galaxies

    NASA Astrophysics Data System (ADS)

    Rude, Cody Millard

    The evolution of galaxies in dense environments can be affected by close encounters with neighboring galaxies and interactions with the intracluster medium (ICM). Dwarf galaxies may be especially susceptible to these effects due to their low mass. The goal of my dissertation research is to look for signs of star formation in cluster dwarf galaxies by measuring and comparing the r- and u-band luminosity functions of 15 low redshift Abell galaxy clusters using archival data from the Canada-France-Hawaii Telescope (CFHT). Luminosity functions, dwarf-to-giant ratios, and blue fractions are measured in four cluster-centric annuli from stacked cluster data. To account for differences in cluster optical richness, each cluster is scaled according to r200, where r200 is the radius of a sphere, centered on the cluster, whose average density is 200 times the critical density of the universe. The outer region of the cluster sample shows an increase in the faint-end slope of the u-band luminosity function relative to the r-band, indicating star formation in dwarf galaxies. The blue fraction for dwarf galaxies steadily rises with increasing cluster-centric radii. The change in the blue fraction of giant galaxies also increases, but at a lower rate. Additionally, the inner regions of clusters ranging from 0.185 < z < 0.7 from the "Cluster Lensing and Supernova survey with Hubble (CLASH)" are used to generate blue- and red-band luminosity functions, dwarf-to-giant ratios, and blue fractions. Comparisons of the inner region of the CLASH and CFHT clusters show an increase in the blue fraction of dwarf galaxies with redshift that is not present in giant galaxies.

  5. An optical view of the filament region of Abell 85

    NASA Astrophysics Data System (ADS)

    Boué, G.; Durret, F.; Adami, C.; Mamon, G. A.; Ilbert, O.; Cayatte, V.

    2008-10-01

    Aims: We present an optical investigation of the Abell 85 cluster filament (z = 0.055) previously interpreted in X-rays as groups falling on to the main cluster. We compare the distribution of galaxies with the X-ray filament, and investigate the galaxy luminosity functions in several bands and in several regions. We search for galaxies where star formation may have been triggered by interactions with intracluster gas or tidal pressure due to the cluster potential when entering the cluster. Methods: Our analysis is based on images covering the South tip of Abell 85 and its infalling filament, obtained with CFHT MegaPrime/MegaCam (1×1 deg2 field) in four bands (u^*, g', r', i') and ESO 2.2 m WFI (38×36 arcmin2 field) in a narrow band filter corresponding to the redshifted Hα line and in an RC broad band filter. The LFs are estimated by statistically subtracting a reference field. Background contamination is minimized by cutting out galaxies redder than the observed red sequence in the g'-i' versus i' colour-magnitude diagram. Results: The galaxy distribution shows a significantly flattened cluster, whose principal axis is slightly offset from the X-ray filament. The analysis of the broad band galaxy luminosity functions shows that the filament region is well populated. The filament is also independently detected as a gravitationally bound structure by the Serna & Gerbal (1996, A&A, 309, 65) hierarchical method. 101 galaxies are detected in the Hα filter, among which 23 have spectroscopic redshifts in the cluster, 2 have spectroscopic redshifts higher than the cluster and 58 have photometric redshifts that tend to indicate that they are background objects. One galaxy that is not detected in the Hα filter probably because of the filter low wavelength cut but shows Hα emission in its SDSS spectrum in the cluster redshift range has been added to our sample. The 24 galaxies with spectroscopic redshifts in the cluster are mostly concentrated in the South part of the

  6. Chandra Observations of Point Sources in Abell 2255

    NASA Technical Reports Server (NTRS)

    Davis, David S.; Miller, Neal A.; Mushotzky, Richard F.

    2003-01-01

    In our search for "hidden" AGN we present results from a Chandra observation of the nearby cluster Abell 2255. Eight cluster galaxies are associated with point-like X-ray emission, and we classify these galaxies based on their X-ray, radio, and optical properties. At least three are associated with active galactic nuclei (AGN) with no optical signatures of nuclear activity, with a further two being potential AGN. Of the potential AGN, one corresponds to a galaxy with a post-starburst optical spectrum. The remaining three X-ray detected cluster galaxies consist of two starbursts and an elliptical with luminous hot gas. Of the eight cluster galaxies five are associated with luminous (massive) galaxies and the remaining three lie in much lower luminosity systems. We note that the use of X-ray to optical flux ratios for classification of X-ray sources is often misleading, and strengthen the claim that the fraction of cluster galaxies hosting an AGN based on optical data is significantly lower than the fraction based on X-ray and radio data.

  7. Abel's Theorem Simplifies Reduction of Order

    ERIC Educational Resources Information Center

    Green, William R.

    2011-01-01

    We give an alternative to the standard method of reduction or order, in which one uses one solution of a homogeneous, linear, second order differential equation to find a second, linearly independent solution. Our method, based on Abel's Theorem, is shorter, less complex and extends to higher order equations.

  8. Gas Sloshing in Abell 2204: Constraining the Properties of the Magnetized Intracluster Medium

    NASA Astrophysics Data System (ADS)

    Chen, Huanqing; Jones, Christine; Andrade-Santos, Felipe; ZuHone, John A.; Li, Zhiyuan

    2017-03-01

    The rich galaxy cluster Abell 2204 exhibits edges in its X-ray surface brightness at ∼65 and 35 {kpc} west and east of its center, respectively. The presence of these edges, which were interpreted as sloshing cold fronts, implies that the intracluster medium (ICM) was recently disturbed. We analyze the properties of the ICM using multiple Chandra observations of Abell 2204. We find a density ratio of {n}{in}/{n}{out}=2.05+/- 0.05 and a temperature ratio of {T}{out}/{T}{in}=1.91+/- 0.27 (projected, or 1.87 ± 0.56 deprojected) across the western edge, and correspondingly {n}{in}/{n}{out}=1.96+/- 0.05 and {T}{out}/{T}{in}=1.45+/- 0.15 (projected, or 1.25 ± 0.26 deprojected) across the eastern edge. These values are typical of cold fronts in galaxy clusters. This, together with the spiral pattern observed in the cluster core, supports the sloshing scenario for Abell 2204. No Kelvin–Helmholtz eddies are observed along the cold front surfaces, indicating that they are effectively suppressed by some physical mechanism. We argue that the suppression is likely facilitated by the magnetic fields amplified in the sloshing motion and deduce from the measured gas properties that the magnetic field strength should be greater than 24 ± 6 μG and 32 ± 8 μG along the west and east cold fronts, respectively.

  9. On the Evolutionary Status of the Early-type Galaxy Population in Abell 2390

    NASA Astrophysics Data System (ADS)

    Fritz, Alexander; Ziegler, Bodo L.; Bower, Richard G.; Smail, Ian; Davies, Roger L.

    2003-08-01

    Using a combination of Multi-Object-Spectroscopy (MOS) with MOSCA at the 3.5m telescope on Calar Alto Observatory, deep ground-based imaging with the 5.1m Hale telescope at Palomar Observatory and HST observations in the F555W (B) and F814W (I) filters, a large sample of N=51 early-type galaxies in the rich cluster Abell 2390 at a redshift z=0.23 is investigated. Our study spans both a broad range in luminosity (-19.3>=M_{B}>=-22.3) and a wide field-of-view (10' x 10'). Therefore, the environmental dependence of different formation scenarios can be analysed in detail as a function of radius from the cluster centre as well as for different sub-populations. In this article we present the motivation for this investigation, give an overview of the sample selection and observations and present our findings for the Fundamental Plane of early-type galaxies for the intermediate redshift clusters Abell 2218 and Abell 2390 at z~0.2.

  10. THE CLUSTER LENSING AND SUPERNOVA SURVEY WITH HUBBLE (CLASH): STRONG-LENSING ANALYSIS OF A383 FROM 16-BAND HST/WFC3/ACS IMAGING

    SciTech Connect

    Zitrin, A.; Broadhurst, T.; Coe, D.; Postman, M.; Bradley, L.; Koekemoer, A.; Umetsu, K.; Benitez, N.; Molino, A.; Meneghetti, M.; Medezinski, E.; Zheng, W.; Ford, H.; Lemze, D.; Jouvel, S.; Lahav, O.; Merten, J.; Kelson, D.; Nonino, M.; Donahue, M.; and others

    2011-12-01

    We examine the inner mass distribution of the relaxed galaxy cluster A383 (z = 0.189), in deep 16 band Hubble Space Telescope/ACS+WFC3 imaging taken as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) multi-cycle treasury program. Our program is designed to study the dark matter distribution in 25 massive clusters, and balances depth with a wide wavelength coverage, 2000-16000 A, to better identify lensed systems and generate precise photometric redshifts. This photometric information together with the predictive strength of our strong-lensing analysis method identifies 13 new multiply lensed images and candidates, so that a total of 27 multiple images of nine systems are used to tightly constrain the inner mass profile gradient, dlog {Sigma}/dlog r {approx_equal} -0.6 {+-} 0.1 (r < 160 kpc). We find consistency with the standard distance-redshift relation for the full range spanned by the lensed images, 1.01 < z < 6.03, with the higher-redshift sources deflected through larger angles as expected. The inner mass profile derived here is consistent with the results of our independent weak-lensing analysis of wide-field Subaru images, with good agreement in the region of overlap ({approx}0.7-1 arcmin). Combining weak and strong lensing, the overall mass profile is well fitted by a Navarro-Frenk-White profile with M{sub vir} = (5.37{sup +0.70}{sub -0.63} {+-} 0.26) Multiplication-Sign 10{sup 14} M{sub Sun} h{sup -1} and a relatively high concentration, c{sub vir} = 8.77{sup +0.44}{sub -0.42} {+-} 0.23, which lies above the standard c-M relation similar to other well-studied clusters. The critical radius of A383 is modest by the standards of other lensing clusters, r{sub E} {approx_equal} 16 {+-} 2'' (for z{sub s} = 2.55), so the relatively large number of lensed images uncovered here with precise photometric redshifts validates our imaging strategy for the CLASH survey. In total we aim to provide similarly high-quality lensing data for 25 clusters

  11. Aspherical supernovae

    SciTech Connect

    Kasen, Daniel Nathan

    2004-01-01

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3) And

  12. Supernova Neutrinos

    SciTech Connect

    Beacom, John

    2009-11-14

    Supernovae in our Galaxy probably occur about 3 times per century, though 90% of them are invisible optically because of obscuration by dust. However, present solar neutrino detectors are sensitive to core-collapse supernovae anywhere in our Galaxy, and would detect of order 10,000 events from a supernova at a distance of 10 kpc (roughly the distance to the Galactic center). I will describe how this data can be used to understand the supernova itself, as well as to test the properties of neutrinos.

  13. The Sunyaev-Zeldovich Effect in Abell 370

    NASA Technical Reports Server (NTRS)

    Grego, Laura; Carlstrom, John E.; Joy, Marshall K.; Reese, Erik D.; Holder, Gilbert P.; Patel, Sandeep; Cooray, Asantha R.; Holzappel, William L.

    2000-01-01

    We present interferometric measurements of the Sunyaev-Zeldovich (SZ) effect toward the galaxy cluster Abell 370. These measurements, which directly probe the pressure of the cluster's gas, show the gas distribution to be strongly aspherical, as do the X-ray and gravitational lensing observations. We calculate the cluster's gas mass fraction in two ways. We first compare the gas mass derived from the SZ measurements to the lensing-derived gravitational mass near the critical lensing radius. We also calculate the gas mass fraction from the SZ data by deprojecting the three-dimensional gas density distribution and deriving the total mass under the assumption that the gas is in hydrostatic equilibrium (HSE). We test the assumptions in the HSE method by comparing the total cluster mass implied by the two methods and find that they agree within the errors of the measurement. We discuss the possible system- atic errors in the gas mass fraction measurement and the constraints it places on the matter density parameter, Omega(sub M).

  14. A series of shocks and edges in Abell 2219

    NASA Astrophysics Data System (ADS)

    Canning, R. E. A.; Allen, S. W.; Applegate, D. E.; Kelly, P. L.; von der Linden, A.; Mantz, A.; Million, E.; Morris, R. G.; Russell, H. R.

    2017-01-01

    We present deep, 170 ks, Chandra X-ray observations of Abell 2219 (z = 0.23), one of the hottest and most X-ray luminous clusters known, and which is experiencing a major merger event. We discover a `horseshoe' of high-temperature gas surrounding the ram-pressure-stripped, bright, hot, X-ray cores. We confirm an X-ray shock front located north-west of the X-ray centroid and along the projected merger axis. We also find a second shock front to the south-east of the X-ray centroid making this only the second cluster where both the shock and reverse shock are confirmed with X-ray temperature measurements. We also present evidence for a possible sloshing cold front in the `remnant tail' of one of the sub-cluster cores. The cold front and north-west shock front geometrically bound the radio halo and appear to be directly influencing the radio properties of the cluster.

  15. Detection of a radio bridge in Abell 3667

    NASA Astrophysics Data System (ADS)

    Carretti, E.; Brown, S.; Staveley-Smith, L.; Malarecki, J. M.; Bernardi, G.; Gaensler, B. M.; Haverkorn, M.; Kesteven, M. J.; Poppi, S.

    2013-04-01

    We have detected a radio bridge of unpolarized synchrotron emission connecting the NW relic of the galaxy cluster Abell 3667 to its central regions. We used data at 2.3 GHz from the S-band Polarization All Sky Survey and at 3.3 GHz from a follow-up observation, both conducted with the Parkes radio telescope. This emission is further aligned with a diffuse X-ray tail, and represents the most compelling evidence for an association between intracluster medium turbulence and diffuse synchrotron emission. This is the first clear detection of a bridge associated both with an outlying cluster relic and X-ray diffuse emission. All the indicators point towards the synchrotron bridge being related to the post-shock turbulent wake trailing the shock front generated by a major merger in a massive cluster. Although predicted by simulations, this is the first time such emission is detected with high significance and clearly associated with the path of a confirmed shock. Although the origin of the relativistic electrons is still unknown, the turbulent re-acceleration model provides a natural explanation for the large-scale emission. The equipartition magnetic field intensity of the bridge is Beq = 2.2 ± 0.3 μG. We further detect diffuse emission coincident with the central regions of the cluster for the first time.

  16. Chandra Observation of the WAT Radio Source/ICM Interaction in Abell 623

    NASA Astrophysics Data System (ADS)

    Anand, Gagandeep; Blanton, Elizabeth L.; Randall, Scott W.; Paterno-Mahler, Rachel; Douglass, Edmund

    2017-01-01

    Galaxy clusters are important objects for studying the physics of the intracluster medium (ICM), galaxy formation and evolution, and cosmological parameters. Clusters containing wide-angle tail (WAT) radio sources are particularly valuable for studies of the interaction between these sources and the surrounding ICM. These sources are thought to form when the ram pressure from the ICM caused by the relative motion between the host radio galaxy and the cluster bends the radio lobes into a distinct wide-angle morphology. We present our results from the analysis of a Chandra observation of the nearby WAT hosting galaxy cluster Abell 623. A clear decrement in X-ray emission is coincident with the southern radio lobe, consistent with being a cavity carved out by the radio source. We present profiles of surface brightness, temperature, density, and pressure and find evidence for a possible shock. Based on the X-ray pressure in the vicinity of the radio lobes and assumptions about the content of the lobes, we estimate the relative ICM velocity required to bend the lobes into the observed angle. We also present spectral model fits to the overall diffuse cluster emission and see no strong signature for a cool core. The sum of the evidence indicates that Abell 623 may be undergoing a large scale cluster-cluster merger.

  17. The Sunyaev-Zel'dovich Effect in Abell 370

    NASA Technical Reports Server (NTRS)

    Grego, Laura; Carlstrom, John E.; Joy, Marshall K.; Reese, Erik D.; Holder, Gilbert P.; Patel, Sandeep; Holzapfel, William L.; Cooray, Asantha K.

    1999-01-01

    We present interferometric measurements of the Sunyaev-Zel'dovich (SZ) effect towards the galaxy cluster Abell 370. These measurements, which directly probe the pressure of the cluster's gas, show the gas is strongly aspherical, on agreement with the morphology revealed by x-ray and gravitational lensing observations. We calculate the cluster's gas mass fraction by comparing the gas mass derived from the SZ measurements to the lensing-derived gravitational mass near the critical lensing radius. We also calculate the gas mass fraction from the SZ data by deriving the total mass under the assumption that the gas is in hydrostatic equilibrium (HSE). We test the assumptions in the HSE method by comparing the total cluster mass implied by the two methods. The Hubble constant derived for this cluster, when the known systematic uncertainties are included, has a very wide range of values and therefore does not provide additional constraints on the validity of the assumptions. We examine carefully the possible systematic errors in the gas fraction measurement. The gas fraction is a lower limit to the cluster's baryon fraction and so we compare the gas mass fraction, calibrated by numerical simulations to approximately the virial radius, to measurements of the global mass fraction of baryonic matter, OMEGA(sub B)/OMEGA(sub matter). Our lower limit to the cluster baryon fraction is f(sub B) = (0.043 +/- 0.014)/h (sub 100). From this, we derive an upper limit to the universal matter density, OMEGA(sub matter) <= 0.72/h(sub 100), and a likely value of OMEGA(sub matter) <= (0.44(sup 0.15, sub -0.12)/h(sub 100).

  18. GSFC Contributions to the NATO X-ray Astronomy Institute, Erice, July 1979. [X-ray spectra of supernova remants, galactic X-ray sources, active galactic nuclei, and clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Mushotzky, R. F.

    1979-01-01

    An overview of X-ray astronomical spectroscopy in general is presented and results obtained by HEAO 1 and 2 as well as earlier spacecraft are examined. Particular emphasis is given to the spectra of supernova remnants; galactic binary X-ray sources, cataclysmic variables, bulges, pulsars, and stars; the active nuclei of Seyfert 1 galaxy, BL Lac, and quasars; the diffuse X-ray background; and galactic clusters.

  19. ABELL 1201: A MINOR MERGER AT SECOND CORE PASSAGE

    SciTech Connect

    Ma Chengjiun; Nulsen, Paul E. J.; McNamara, Brian R.; Murray, Stephen S.; Owers, Matt; Couch, Warrick J.

    2012-06-20

    We present an analysis of the structures and dynamics of the merging cluster Abell 1201, which has two sloshing cold fronts around a cooling core, and an offset gas core approximately 500 kpc northwest of the center. New Chandra and XMM-Newton data reveal a region of enhanced brightness east of the offset core, with breaks in surface brightness along its boundary to the north and east. This is interpreted as a tail of gas stripped from the offset core. Gas in the offset core and the tail is distinguished from other gas at the same distance from the cluster center chiefly by having higher density, hence lower entropy. In addition, the offset core shows marginally lower temperature and metallicity than the surrounding area. The metallicity in the cool core is high and there is an abrupt drop in metallicity across the southern cold front. We interpret the observed properties of the system, including the placement of the cold fronts, the offset core, and its tail in terms of a simple merger scenario. The offset core is the remnant of a merging subcluster, which first passed pericenter southeast of the center of the primary cluster and is now close to its second pericenter passage, moving at {approx_equal} 1000 km s{sup -1}. Sloshing excited by the merger gave rise to the two cold fronts and the disposition of the cold fronts reveals that we view the merger from close to the plane of the orbit of the offset core.

  20. A shock at the radio relic position in Abell 115

    NASA Astrophysics Data System (ADS)

    Botteon, A.; Gastaldello, F.; Brunetti, G.; Dallacasa, D.

    2016-07-01

    We analysed a deep Chandra observation (334 ks) of the galaxy cluster Abell 115 and detected a shock cospatial with the radio relic. The X-ray surface brightness profile across the shock region presents a discontinuity, corresponding to a density compression factor C=2.0± 0.1, leading to a Mach number M=1.7± 0.1 (M=1.4-2 including systematics). Temperatures measured in the upstream and downstream regions are consistent with what expected for such a shock: Tu=4.3+1.0-0.6 keV and Td=7.9+1.4-1.1 keV, respectively, implying a Mach number M=1.8+0.5-0.4. So far, only few other shocks discovered in galaxy clusters are consistently detected from both density and temperature jumps. The spatial coincidence between this discontinuity and the radio relic edge strongly supports the view that shocks play a crucial role in powering these synchrotron sources. We suggest that the relic is originated by shock re-acceleration of relativistic electrons rather than acceleration from the thermal pool. The position and curvature of the shock and the associated relic are consistent with an off-axis merger with unequal mass ratio where the shock is expected to bend around the core of the less massive cluster.

  1. The Sunyaev-Zel'dovich Effect Spectrum of Abell 2163

    NASA Technical Reports Server (NTRS)

    LaRoque, S. J.; Carlstrom, J. E.; Reese, E. D.; Holder, G. P.; Holzapfel, W. L.; Joy, M.; Grego, L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We present an interferometric measurement of the Sunyaev-Zel'dovich effect (SZE) at 1 cm for the galaxy cluster Abell 2163. We combine this data point with previous measurements at 1.1, 1.4, and 2.1 mm from the SuZIE experiment to construct the most complete SZE spectrum to date. The intensity in four wavelength bands is fit to determine the Compton y-parameter (y(sub 0)) and the peculiar velocity (v(sub p)) for this cluster. Our results are y(sub 0) = 3.56((sup +0.41+0.27)(sub -0.41-0.19)) X 10(exp -4) and v(sub p) = 410((sup +1030+460) (sub -850-440)) km s(exp -1) where we list statistical and systematic uncertainties, respectively, at 68% confidence. These results include corrections for contamination by Galactic dust emission. We find less contamination by dust emission than previously reported. The dust emission is distributed over much larger angular scales than the cluster signal and contributes little to the measured signal when the details of the SZE observing strategy are taken into account.

  2. A free-form prediction for the reappearance of supernova Refsdal in the Hubble Frontier Fields cluster MACSJ1149.5+2223

    NASA Astrophysics Data System (ADS)

    Diego, Jose M.; Broadhurst, Tom; Chen, Cuncheng; Lim, Jeremy; Zitrin, Adi; Chan, Brian; Coe, Dan; Ford, Holland C.; Lam, Daniel; Zheng, Wei

    2016-02-01

    The massive cluster MACSJ1149.5+2223(z = 0.544) displays five very large lensed images of a well-resolved spiral galaxy at zspect = 1.491. It is within one of these images that the first example of a multiply lensed supernova (SN) has been detected recently as part of the Grism Lens-Amplified Survey from Space. The depth of this data also reveals many H II regions within the lensed spiral galaxy which we identify between the five counter-images. Here, we expand the capability of our free-form method to incorporate these H II regions locally, with other reliable lensed galaxies added for a global solution. This improved accuracy allows us to estimate when the Refsdal SN will appear within the other lensed images of the spiral galaxy to an accuracy of ˜7 per cent. We predict this SN will reappear in one of the counter-images (RA = 11:49:36.025, Dec. = +22:23:48.11, J2000) and on 2015 November 1 (with an estimated error of ±25 d) it will be at the same phase as it was when it was originally discovered, offering a unique opportunity to study the early phases of this SN and to examine the consistency of the mass model and the cosmological model that have an impact on the time delay prediction.

  3. Data-driven approach to Type Ia supernovae: variable selection on the peak luminosity and clustering in visual analytics

    NASA Astrophysics Data System (ADS)

    Uemura, Makoto; Kawabata, Koji S.; Ikeda, Shiro; Maeda, Keiichi; Wu, Hsiang-Yun; Watanabe, Kazuho; Takahashi, Shigeo; Fujishiro, Issei

    2016-03-01

    Type Ia supernovae (SNIa) have an almost uniform peak luminosity, so that they are used as “standard candle” to estimate distances to galaxies in cosmology. In this article, we introduce our two recent works on SNIa based on data-driven approach. The diversity in the peak luminosity of SNIa can be reduced by corrections in several variables. The color and decay rate have been used as the explanatory variables of the peak luminosity in past studies. However, it is proposed that their spectral data could give a better model of the peak luminosity. We use cross-validation in order to control the generalization error and a LASSO-type estimator in order to choose the set of variables. Using 78 samples and 276 candidates of variables, we confirm that the peak luminosity depends on the color and decay rate. Our analysis does not support adding any other variables in order to have a better generalization error. On the other hand, this analysis is based on the assumption that SNIa originate in a single population, while it is not trivial. Indeed, several sub-types possibly having different nature have been proposed. We used a visual analytics tool for the asymmetric biclustering method to find both a good set of variables and samples at the same time. Using 14 variables and 132 samples, we found that SNIa can be divided into two categories by the expansion velocity of ejecta. Those examples demonstrate that the data-driven approach is useful for high-dimensional large-volume data which becomes common in modern astronomy.

  4. Supernova models

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1980-01-01

    Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the /sup 56/Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed.

  5. Supernova Neutrinos

    SciTech Connect

    Cardall, Christian Y

    2007-01-01

    A nascent neutron star resulting from stellar collapse is a prodigious source of neutrinos of all flavors. While the most basic features of this neutrino emission can be estimated from simple considerations, the detailed simulation of the neutrinos' decoupling from the hot neutron star is not yet computationally tractable in its full glory, being a time-dependent six-dimensional transport problem. Nevertheless, supernova neutrino fluxes are of great interest in connection with the core-collapse supernova explosion mechanism and supernova nucleosynthesis, and as a potential probe of the supernova environment and of some of the neutrino mixing parameters that remain unknown; hence, a variety of approximate transport schemes have been used to obtain results with reduced dimensionality. However, none of these approximate schemes have addressed a recent challenge to the conventional wisdom that neutrino flavor mixing cannot impact the explosion mechanism or r-process nucleosynthesis.

  6. Revised Lens Model and Predictions of Time Delay for the Multiply Imaged Lensed Supernova, “SN Refsdal”, in the FF cluster MACS J1149+2223

    NASA Astrophysics Data System (ADS)

    Sharon, Keren; Johnson, Traci Lin

    2015-08-01

    We present a revised lens model of MACS J1149+2223, in which the first resolved multiply imaged lensed supernova (SN) was discovered. The lens model is based on the model of Johnson et al. with some modifications. We include more lensing constraints from the host galaxy of the newly discovered SN, and increase the flexibility of the model in order to better reproduce the lensing signal in the vicinity of this galaxy. The revised model accurately reconstructs the positions of the lensed SN, provides magnifications, predicts the time delay between the instances of the SN, and derive their uncertainties. We find that the time delays between the four observed images are a few days: t(S2) = 2 +10/-6 days, t(S3)=-5 +13/-7 days, t(S4)=7 +16/-3 days. At the positions of the other images of the same host galaxy, an image of the SN had appeared on the opposite side of the cluster some 11-13 years ago, and another is predicted to appear approximately 180-280 days after S1, i.e., in a 3-month window around July 2015. This image will be less magnified than the ones already detected, with magnification of mu=5 (compared to mu~10-20 of the four images that were observed in 2014, making it about three times fainter). Finally, we reconstruct the source image of the host galaxy, and position the SN on one of its spiral arms. New lensing constraints from the full depth FF imaging will improve the accuracy of future lens models. Products of this lens model are available to the community through MAST.

  7. MINOR MERGER-INDUCED COLD FRONTS IN ABELL 2142 AND RXJ1720.1+2638

    SciTech Connect

    Owers, Matt S.; Couch, Warrick J.; Nulsen, Paul E. J.

    2011-11-10

    We present evidence for the existence of substructure in the 'relaxed appearing' cold front clusters Abell 2142 and RXJ1720.1+2638. The detection of these substructures was made possible by comprehensive multi-object optical spectroscopy obtained with the Hectospec and DEep Imaging Multi-Object Spectrograph instruments on the 6.5 m MMT and 10 m Keck II telescope, respectively. These observations produced 956 and 400 spectroscopically confirmed cluster members within a projected radius of 3 Mpc from the centers of A2142 and RXJ1720.1+2638, respectively. The substructure manifests itself as local peaks in the spatial distribution of member galaxies and also as regions of localized velocity substructure. For both Abell 2142 and RXJ1720.1+2638, we identify group-scale substructures which, when considering the morphology of the cold fronts and the time since pericentric passage of a perturber estimated from the cold front radii, could plausibly have perturbed the cluster cores and generated the cold fronts observed in Chandra images. The results presented here are consistent with cold fronts being the result of merger activity and with cold fronts in relaxed appearing clusters being due to minor merger activity.

  8. The Herschel Lensing Survey (HLS): A Bright Lensed Submillimeter Galaxy in the Field of Abell 773

    NASA Astrophysics Data System (ADS)

    Rawle, Tim; Egami, E.; Rex, M.; Combes, F.; Boone, F.; Smail, I.; Lensing Survey, Herschel

    2012-05-01

    The Herschel Lensing Survey (HLS; PI: Egami) is observing more than 50 massive galaxy clusters with deep PACS and SPIRE (100-500um) imaging, and a further 500 clusters in a SPIRE snapshot program ( 20 deg^2 of far-infrared cluster observations in total). Here, we present a discussion of an exceptionally bright ( 200mJy at 500um) source behind the cluster Abell 773, which is a strongly lensed submillimeter galaxy (SMG) at z=5.2. The source has an intrinsic infrared luminosity L_FIR 1e13 L_sun, with a total magnification factor of 11. We combine Herschel-SMA-IRAM observations of the dust continuum and gas excitation line emission, including multiple CO transitions, [CII] and [NII] (detected for the first time at high-z), to explore the morphology, star formation and ISM in this SMG.

  9. Shocks, Ripples, and Bubbles: A Very Deep Observation of Abell 2052

    NASA Astrophysics Data System (ADS)

    Blanton, Elizabeth

    2008-09-01

    The cooling flow cluster A2052 has, arguably, the morphology most similar to the Perseus cluster as seen with Chandra. Two clear bubbles to the N and S of the center of A2052 are filled with the radio lobes associated with 3C 317. Surface brightness discontinuities consistent with shocks with Mach numbers of 1.8 and 1.2 are seen near the cluster center. These may be isothermal shocks. We propose to observe Abell 2052 much more deeply to study these shock features, ripple features due to sound waves that may be found at larger radii, possible ghost bubbles, cooling gas in the bright shells around the radio source that may link the X-ray and H-alpha emission, and possible hot gas within the X-ray holes. We will directly compare the star formation and cooling rates in the cluster center.

  10. Luminous supernovae.

    PubMed

    Gal-Yam, Avishay

    2012-08-24

    Supernovae, the luminous explosions of stars, have been observed since antiquity. However, various examples of superluminous supernovae (SLSNe; luminosities >7 × 10(43) ergs per second) have only recently been documented. From the accumulated evidence, SLSNe can be classified as radioactively powered (SLSN-R), hydrogen-rich (SLSN-II), and hydrogen-poor (SLSN-I, the most luminous class). The SLSN-II and SLSN-I classes are more common, whereas the SLSN-R class is better understood. The physical origins of the extreme luminosity emitted by SLSNe are a focus of current research.

  11. Deep Westerbork observations of Abell 2256 at 350 MHz

    NASA Astrophysics Data System (ADS)

    Brentjens, M. A.

    2008-10-01

    Deep polarimetric Westerbork observations of the galaxy cluster Abell 2256 are presented, covering a frequency range of 325-377 MHz. The central halo source has a diameter of the order of 1.2 Mpc (18´), which is somewhat larger than at 1.4 GHz. With α = -1.61±0.04, the halo spectrum between 1.4 GHz and 22.25 MHz is less steep than previously thought. The centre of the ultra steep spectrum source in the eastern part of the cluster exhibits a spectral break near 400 MHz. It is estimated to be at least 51 million years old, but possibly older than 125 million years. A final measurement requires observations in the 10-150 MHz range. It remains uncertain whether the source is a radio tail of Fabricant galaxy 122, situated in the northeastern tip of the source. Faraday rotation measure synthesis revealed no polarized flux at all in the cluster. The polarization fraction of the brightest parts of the relic area is less than 1%. The RM-synthesis nevertheless revealed 9 polarized sources in the field enabling an accurate measurement of the Galactic Faraday rotation (-33±2 rad m-2 in front of the relic). Based on its depolarization on longer wavelengths, the line-of-sight magnetic field in relic filament G is estimated to be between 0.02 and 2 μG. A value of 0.2 μG appears most reasonable given the currently available data.

  12. Revisiting Abell 2744: a powerful synergy of GLASS spectroscopy and HFF photometry

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Wang

    We present new emission line identifications and improve the lensing reconstruction of the mass distribution of galaxy cluster Abell 2744 using the Grism Lens-Amplified Survey from Space (GLASS) spectroscopy and the Hubble Frontier Fields (HFF) imaging. We performed blind and targeted searches for faint line emitters on all objects, including the arc sample, within the field of view (FoV) of GLASS prime pointings. We report 55 high quality spectroscopic redshifts, 5 of which are for arc images. We also present an extensive analysis based on the HFF photometry, measuring the colors and photometric redshifts of all objects within the FoV, and comparing the spectroscopic and photometric redshift estimates. In order to improve the lens model of Abell 2744, we develop a rigorous algorithm to screen arc images, based on their colors and morphology, and selecting the most reliable ones to use. As a result, 25 systems (corresponding to 72 images) pass the screening process and are used to reconstruct the gravitational potential of the cluster pixellated on an adaptive mesh. The resulting total mass distribution is compared with a stellar mass map obtained from the Spitzer Frontier Fields data in order to study the relative distribution of stars and dark matter in the cluster.

  13. Shedding light on the matter of Abell 781

    NASA Astrophysics Data System (ADS)

    Wittman, D.; Dawson, William; Benson, Bryant

    2014-02-01

    The galaxy cluster Abell 781 West has been viewed as a challenge to weak gravitational lensing mass calibration, as Cook & dell'Antonio found that the weak lensing signal-to-noise ratio in three independent sets of observations was consistently lower than expected from mass models based on X-ray and dynamical measurements. We correct some errors in statistical inference in Cook & dell'Antonio and show that their own results agree well with the dynamical mass and exhibit at most 2.2-2.9σ low compared to the X-ray mass, similar to the tension between the dynamical and X-ray masses. Replacing their simple magnitude cut with weights based on source photometric redshifts eliminates the tension between lensing and X-ray masses; in this case the weak lensing mass estimate is actually higher than, but still in agreement with, the dynamical estimate. A comparison of lensing analyses with and without photometric redshifts shows that a 1-2σ chance alignment of low-redshift sources lowers the signal-to-noise ratio observed by all previous studies which used magnitude cuts rather than photometric redshifts. The fluctuation is unexceptional, but appeared to be highly significant in Cook & dell'Antonio due to the errors in statistical interpretation.

  14. A plethora of diffuse steep spectrum radio sources in Abell 2034 revealed by LOFAR

    NASA Astrophysics Data System (ADS)

    Shimwell, T. W.; Luckin, J.; Brüggen, M.; Brunetti, G.; Intema, H. T.; Owers, M. S.; Röttgering, H. J. A.; Stroe, A.; van Weeren, R. J.; Williams, W. L.; Cassano, R.; de Gasperin, F.; Heald, G. H.; Hoang, D. N.; Hardcastle, M. J.; Sridhar, S. S.; Sabater, J.; Best, P. N.; Bonafede, A.; Chyży, K. T.; Enßlin, T. A.; Ferrari, C.; Haverkorn, M.; Hoeft, M.; Horellou, C.; McKean, J. P.; Morabito, L. K.; Orrù, E.; Pizzo, R.; Retana-Montenegro, E.; White, G. J.

    2016-06-01

    With Low-Frequency Array (LOFAR) observations, we have discovered a diverse assembly of steep spectrum emission that is apparently associated with the intracluster medium (ICM) of the merging galaxy cluster Abell 2034. Such a rich variety of complex emission associated with the ICM has been observed in few other clusters. This not only indicates that Abell 2034 is a more interesting and complex system than previously thought but it also demonstrates the importance of sensitive and high-resolution, low-frequency observations. These observations can reveal emission from relativistic particles which have been accelerated to sufficient energy to produce observable emission or have had their high energy maintained by mechanisms in the ICM. The most prominent feature in our maps is a bright bulb of emission connected to two steep spectrum filamentary structures, the longest of which extends perpendicular to the merger axis for 0.5 Mpc across the south of the cluster. The origin of these objects is unclear, with no shock detected in the X-ray images and no obvious connection with cluster galaxies or AGNs. We also find that the X-ray bright region of the cluster coincides with a giant radio halo with an irregular morphology and a very steep spectrum. In addition, the cluster hosts up to three possible radio relics, which are misaligned with the cluster X-ray emission. Finally, we have identified multiple regions of emission with a very steep spectral index that seem to be associated with either tailed radio galaxies or a shock.

  15. Astronomical Resources: Supernovae.

    ERIC Educational Resources Information Center

    Fraknoi, Andrew

    1987-01-01

    Contains a partially annotated, nontechnical bibliography of recent materials about supernovae, including some about the discovery of a supernova in the Large Magellanic Cloud. Includes citations of general books and articles about supernovae, articles about Supernova 1987A, and a few science fiction stories using supernovae. (TW)

  16. Simulating Supernova Light Curves

    SciTech Connect

    Even, Wesley Paul; Dolence, Joshua C.

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  17. Mass dependent galaxy transformation mechanisms in the complex environment of SuperGroup Abell 1882

    NASA Astrophysics Data System (ADS)

    Sengupta, Aparajita

    We present our data and results from panchromatic photometry and optical spectrometry of the nearest (extremely rich) filamentary large scale structure, SuperGroup Abell 1882. It is a precursor of a cluster and is an inevitable part of the narrative in the study of galaxy transformations. There has been strong empirical evidence over the past three decades that galaxy environment affects galaxy properties. Blue disky galaxies transform into red bulge-like galaxies as they traverse into the deeper recesses of a cluster. However, we have little insight into the story of galaxy evolution in the early stages of cluster formation. Besides, in relaxed clusters that have been studied extensively, several evolutionary mechanisms take effect on similar spatial and temporal scales, making it almost impossible to disentangle different local and global mechanisms. A SuperGroup on the other hand, has a shallower dark-matter potential. Here, the accreting galaxies are subjected to evolutionary mechanisms over larger time and spatial scales. This separates processes that are otherwise superimposed in rich cluster-filament interfaces. As has been found from cluster studies, galaxy color and morphology tie very strongly with local galaxy density even in a complex and nascent structure like Abell 1882. Our major results indicate that there is a strong dependence of galaxy transformations on the galaxy masses themselves. Mass- dependent evolutionary mechanisms affect galaxies at different spatial scales. The galaxy color also varies with radial projected distance from the assumed center of the structure for a constant local galaxy density, indicating the underlying large scale structure as a second order evolutionary driver. We have looked for clues to the types of mechanisms that might cause the transformations at various mass regimes. We have found the thoroughly quenched low mass galaxies confined to the groups, whereas there are evidences of intermediate-mass quenched galaxies

  18. The Evolutionary Status of Early-type Galaxies in Abell 2390

    NASA Astrophysics Data System (ADS)

    Fritz, A.; Ziegler, B. L.; Bower, R. G.; Smail, I.; Davies, R. L.

    We explore the evolution of the early-type galaxy population in the rich cluster Abell 2390 at z=0.23. For this purpose, we have obtained spectroscopic data of 51 elliptical and lenticular galaxies with MOSCA at the 3.5 m telescope on Calar Alto Observatory. As our investigation spans both a broad range in luminosity (-22.3<=MB<=-:19.3) and a wide field of view (10'×10'), the environmental dependence of different formation scenarios can be analysed in detail as a function of radius from the cluster center. In this paper, we present first results on the Faber-Jackson relation and, for a subsample of 14 galaxies with morphological and structural parameters from HST, we also investigate the evolution of the Kormendy relation and the Fundamental Plane. We find a mild luminosity evolution of the early-type galaxies in Abell 2390: our objects are on average brighter by mB~0.4 mag.

  19. Abel inversion method for cometary atmospheres.

    NASA Astrophysics Data System (ADS)

    Hubert, Benoit; Opitom, Cyrielle; Hutsemekers, Damien; Jehin, Emmanuel; Munhoven, Guy; Manfroid, Jean; Bisikalo, Dmitry V.; Shematovich, Valery I.

    2016-04-01

    Remote observation of cometary atmospheres produces a measurement of the cometary emissions integrated along the line of sight joining the observing instrument and the gas of the coma. This integration is the so-called Abel transform of the local emission rate. We develop a method specifically adapted to the inversion of the Abel transform of cometary emissions, that retrieves the radial profile of the emission rate of any unabsorbed emission, under the hypothesis of spherical symmetry of the coma. The method uses weighted least squares fitting and analytical results. A Tikhonov regularization technique is applied to reduce the possible effects of noise and ill-conditioning, and standard error propagation techniques are implemented. Several theoretical tests of the inversion techniques are carried out to show its validity and robustness, and show that the method is only weakly dependent on any constant offset added to the data, which reduces the dependence of the retrieved emission rate on the background subtraction. We apply the method to observations of three different comets observed using the TRAPPIST instrument: 103P/ Hartley 2, F6/ Lemmon and A1/ Siding spring. We show that the method retrieves realistic emission rates, and that characteristic lengths and production rates can be derived from the emission rate for both CN and C2 molecules. We show that the emission rate derived from the observed flux of CN emission at 387 nm and from the C2 emission at 514.1 nm of comet Siding Spring both present an easily-identifiable shoulder that corresponds to the separation between pre- and post-outburst gas. As a general result, we show that diagnosing properties and features of the coma using the emission rate is easier than directly using the observed flux. We also determine the parameters of a Haser model fitting the inverted data and fitting the line-of-sight integrated observation, for which we provide the exact analytical expression of the line-of-sight integration

  20. The SAMI Pilot Survey: stellar kinematics of galaxies in Abell 85, 168 and 2399

    NASA Astrophysics Data System (ADS)

    Fogarty, L. M. R.; Scott, N.; Owers, M. S.; Croom, S. M.; Bekki, K.; Houghton, R. C. W.; van de Sande, J.; D'Eugenio, F.; Cecil, G. N.; Colless, M. M.; Bland-Hawthorn, J.; Brough, S.; Cortese, L.; Davies, R. L.; Jones, D. H.; Pracy, M.; Allen, J. T.; Bryant, J. J.; Goodwin, M.; Green, A. W.; Konstantopoulos, I. S.; Lawrence, J. S.; Lorente, N. P. F.; Richards, S.; Sharp, R. G.

    2015-12-01

    We present the SAMI Pilot Survey, consisting of integral field spectroscopy of 106 galaxies across three galaxy clusters, Abell 85, Abell 168 and Abell 2399. The galaxies were selected by absolute magnitude to have Mr < -20.25 mag. The survey, using the Sydney-AAO Multi-object Integral field spectrograph (SAMI), comprises observations of galaxies of all morphological types with 75 per cent of the sample being early-type galaxies (ETGs) and 25 per cent being late-type galaxies (LTGs). Stellar velocity and velocity dispersion maps are derived for all 106 galaxies in the sample. The λR parameter, a proxy for the specific stellar angular momentum, is calculated for each galaxy in the sample. We find a trend between λR and galaxy concentration such that LTGs are less concentrated higher angular momentum systems, with the fast-rotating ETGs (FRs) more concentrated and lower in angular momentum. This suggests that some dynamical processes are involved in transforming LTGs to FRs, though a significant overlap between the λR distributions of these classes of galaxies implies that this is just one piece of a more complicated picture. We measure the kinematic misalignment angle, Ψ, for the ETGs in the sample, to probe the intrinsic shapes of the galaxies. We find the majority of FRs (83 per cent) to be aligned, consistent with them being oblate spheroids (i.e. discs). The slow rotating ETGs (SRs), on the other hand, are significantly more likely to show kinematic misalignment (only 38 per cent are aligned). This confirms previous results that SRs are likely to be mildly triaxial systems.

  1. Precise Strong Lensing Mass Modeling of Four Hubble Frontier Field Clusters and a Sample of Magnified High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Kawamata, Ryota; Oguri, Masamune; Ishigaki, Masafumi; Shimasaku, Kazuhiro; Ouchi, Masami

    2016-03-01

    We conduct precise strong lensing mass modeling of four Hubble Frontier Field (HFF) clusters, Abell 2744, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.6+2223, for which HFF imaging observations are completed. We construct a refined sample of more than 100 multiple images for each cluster by taking advantage of the full-depth HFF images, and conduct mass modeling using the glafic software, which assumes simply parametrized mass distributions. Our mass modeling also exploits a magnification constraint from the lensed SN Ia HFF14Tom for Abell 2744 and positional constraints from the multiple images S1-S4 of the lensed supernova SN Refsdal for MACS J1149.6+2223. We find that our best-fitting mass models reproduce the observed image positions with rms errors of ˜0.″4, which are smaller than rms errors in previous mass modeling that adopted similar numbers of multiple images. Our model predicts a new image of SN Refsdal with a relative time delay and magnification that are fully consistent with a recent detection of reappearance. We then construct catalogs of z ˜ 6-9 dropout galaxies behind the four clusters and estimate magnification factors for these dropout galaxies with our best-fitting mass models. The dropout sample from the four cluster fields contains ˜120 galaxies at z ≳ 6, about 20 of which are predicted to be magnified by a factor of more than 10. Some of the high-redshift galaxies detected in the HFF have lensing-corrected magnitudes of MUV ˜ -15 to -14. Our analysis demonstrates that the HFF data indeed offer an ideal opportunity to study faint high-redshift galaxies. All lensing maps produced from our mass modeling will be made available on the Space Telescope Science Institute website (https://archive.stsci.edu/prepds/frontier/lensmodels/).

  2. The EASE Scenario: Dynamical Study of the Supernova Phase

    NASA Astrophysics Data System (ADS)

    Parmentier, Geneviève; Jehin, Emannuel; Magain, Pierre; Noels, Arlette; Thoul, Anne

    We revisit the most often encountered argument against self-enrichment in globular clusters, namely the ability of a few number of supernovae to disrupt the proto-globular cloud. We show that, within the context of the Fall and Rees theory, primordial proto-globular cluster clouds may sustain several hundreds of Type II supernovae. Furthermore, the corresponding self-enrichment level is in agreement with galactic halo globular cluster metallicities.

  3. The Filtered Abel Transform and Its Application in Combustion Diagnostics

    NASA Technical Reports Server (NTRS)

    Simons, Stephen N. (Technical Monitor); Yuan, Zeng-Guang

    2003-01-01

    Many non-intrusive combustion diagnosis methods generate line-of-sight projections of a flame field. To reconstruct the spatial field of the measured properties, these projections need to be deconvoluted. When the spatial field is axisymmetric, commonly used deconvolution method include the Abel transforms, the onion peeling method and the two-dimensional Fourier transform method and its derivatives such as the filtered back projection methods. This paper proposes a new approach for performing the Abel transform method is developed, which possesses the exactness of the Abel transform and the flexibility of incorporating various filters in the reconstruction process. The Abel transform is an exact method and the simplest among these commonly used methods. It is evinced in this paper that all the exact reconstruction methods for axisymmetric distributions must be equivalent to the Abel transform because of its uniqueness and exactness. Detailed proof is presented to show that the two dimensional Fourier methods when applied to axisymmetric cases is identical to the Abel transform. Discrepancies among various reconstruction method stem from the different approximations made to perform numerical calculations. An equation relating the spectrum of a set of projection date to that of the corresponding spatial distribution is obtained, which shows that the spectrum of the projection is equal to the Abel transform of the spectrum of the corresponding spatial distribution. From the equation, if either the projection or the distribution is bandwidth limited, the other is also bandwidth limited, and both have the same bandwidth. If the two are not bandwidth limited, the Abel transform has a bias against low wave number components in most practical cases. This explains why the Abel transform and all exact deconvolution methods are sensitive to high wave number noises. The filtered Abel transform is based on the fact that the Abel transform of filtered projection data is equal

  4. Discovery of a Star Formation Region in Abell 2052

    NASA Astrophysics Data System (ADS)

    Martel, André R.; Sparks, William B.; Allen, Mark G.; Koekemoer, Anton M.; Baum, Stefi A.

    2002-03-01

    We report the discovery of an ultraviolet filament detected in a new Space Telescope Imaging Spectrograph (STIS) NUV-MAMA image of the cD galaxy UGC 9799, located in the cooling-flow cluster Abell 2052 and host to the radio source 3C 317. The filament is ~2 kpc in length and is located at a distance of ~4 kpc from the nucleus along a north-south axis. It consists of three knots embedded along the edges of a diffuse filamentary halo. The northern half of the filament is narrow (~100 pc) and straight while the southern half is bent and more diffuse. The blue color (NUV-V~-2.4) and morphology of the filament are most consistent with a recent episode of star formation (T~5 Myr). Only a few×104 Msolar of young stars or a star formation rate of ~10-3 Msolar yr-1 is required to produce the feature. A steep ultraviolet halo is detected around the unresolved nucleus, and it may be associated with an old stellar component. No ultraviolet features are identified at the location of the extended emission-line nebulae observed from the ground, indicating that OB stars are not the primary source of ionization in these regions. We consider cooling flows and a merger with a satellite galaxy the trigger for the starburst regions and conclude that the latter is the more consistent with the chaotic dust lanes spread throughout the host galaxy. The star formation observed is orders of magnitude less than the inferred cooling rate in the cooling flow scenario. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  5. The galaxy population of Abell 1367: the stellar mass-metallicity relation

    NASA Astrophysics Data System (ADS)

    Mouhcine, M.; Kriwattanawong, W.; James, P. A.

    2011-04-01

    Using wide baseline broad-band photometry, we analyse the stellar population properties of a sample of 72 galaxies, spanning a wide range of stellar masses and morphological types, in the nearby spiral-rich and dynamically young galaxy cluster Abell 1367. The sample galaxies are distributed from the cluster centre out to approximately half the cluster Abell radius. The optical/near-infrared colours are compared with simple stellar population synthesis models from which the luminosity-weighted stellar population ages and metallicities are determined. The locus of the colours of elliptical galaxies traces a sequence of varying metallicity at a narrow range of luminosity-weighted stellar ages. Lenticular galaxies in the red sequence, however, exhibit a substantial spread of luminosity-weighted stellar metallicities and ages. For red-sequence lenticular galaxies and blue cloud galaxies, low-mass galaxies tend to be on average dominated by stellar populations of younger luminosity-weighted ages. Sample galaxies exhibit a strong correlation between integrated stellar mass and luminosity-weighted stellar metallicity. Galaxies with signs of morphological disturbance and ongoing star formation activity, tend to be underabundant with respect to passive galaxies in the red sequence of comparable stellar masses. We argue that this could be due to tidally driven gas flows towards the star-forming regions, carrying less enriched gas and diluting the pre-existing gas to produce younger stellar populations with lower metallicities than would be obtained prior to the interaction. Finally, we find no statistically significant evidence for changes in the luminosity-weighted ages and metallicities for either red-sequence or blue-cloud galaxies, at fixed stellar mass, with location within the cluster. We dedicate this work to the memory of our friend and colleague C. Moss who died suddenly recently.

  6. Revisiting Abell 2744: a powerful synergy of the GLASS spectroscopy and the HFF photometry.

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Borello Schmidt, Kasper; Treu, Tommaso

    2015-08-01

    We present new emission line identifications and improve the strong lensing reconstruction of the massive cluster Abell 2744 using the Grism Lens-Amplified Survey from Space (GLASS) observations and the full depth of the Hubble Frontier Fields (HFF) imaging. We performed a blind and targeted search for emission lines in objects within the full field of view (FoV) of the GLASS prime pointings, including all the previously known multiple arc images. We report over 50 high quality spectroscopic redshifts, 4 of which are for the arc images. We also present an extensive analysis based on the HFF photometry, measuring the colors and photometric redshifts of all objects within the FoV, and comparing the spectroscopic and photometric results of the same ensemble of sources. In order to improve the lens model of Abell 2744, we develop a rigorous alogorithm to screen arc images, based on their colors and morphology, and selecting the most reliable ones to use. As a result, 21 systems (corresponding to 59 images) pass the screening process and are used to reconstruct the gravitational potential of the cluster pixellated on an adaptive mesh. The resulting total mass distribution is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data in a fashion very similar to the reduction of the Spitzer UltRa Faint SUrvey Program (SURFS UP) clusters, in order to study the relative distribution of stars and dark matter in the cluster. The maps of convergence, shear, and magnification are made publicly available in the standard HFF format.

  7. Detailed modeling of cluster galaxies in free-form lenses

    NASA Astrophysics Data System (ADS)

    Lam, Daniel

    2015-08-01

    The main goal of the Frontier Fields is to characterize the population of high redshift galaxies that are gravitationally lensed and magnified by foreground massive galaxy clusters. The magnification received by lensed images has to be accurately quantified in order to derive the correct science results. The magnification is in turn computed from lens models, which are constructed from various constraints, most commonly the positions and redshifts of multiply-lensed galaxies.The locations and magnification of multiple images that appear near cluster galaxies are very sensitive to the mass distribution of those individual galaxies. In current free-form lens models, they are at best crudely approximated by arbitrary mass halos and are usually being completely neglected. Given sufficient free parameters and iterations, such models may be highly consistent but their predictive power would be rather limited. This shortcoming is particularly pronounced in light of the recent discovery of the first multiply-lensed supernova in the Frontier Fields cluster MACSJ1149. The proximity of its images to cluster galaxies mandates detailed modeling on galaxy-scales, where free-form methods solely based on grid solutions simply fail.We present a hybrid free-form lens model of Abell 2744, which for the first time incorporates a detailed mass component modeled by GALFIT that accurately captures the stellar light distribution of the hundred brightest cluster galaxies. The model better reproduces the image positions than a previous version, which modeled cluster galaxies with simplistic NFW halos. Curiously, this improvement is found in all but system 2, which has two radial images appearing around the BCG. Despite its complex light profile is being captured by GALFIT, the persistent discrepancies suggest considering mass distributions that may be largely offset from the stellar light distribution.

  8. A Detailed Study of the Mass Distribution of the Galaxy Cluster RXC J2248.7-4431

    NASA Astrophysics Data System (ADS)

    Caminha, G. B.; Rosati, P.; Grillo, C.; the CLASH-VLT Team

    2016-02-01

    In this work we use strong gravitational lensing techniques to constrain the total mass distribution of the galaxy cluster RXC J2248.7-4432 (RXC J2248, zlens = 0.348), also known as Abell S1063, observed within the Cluster Lensing And Supernova survey with Hubble (CLASH). Thanks to its strong lensing efficiency and exceptional data quality from the VIsible Multi-Object Spectrograph (VIMOS) and Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope, we can build a parametric model for the total mass distribution. Using the positions of the multiple images generated by 7 multiply-lensed background sources with measured spectroscopic redshifs, we find that the best-fit parametrisation for the cluster total mass distribution is composed of an elliptical pseudo-isothermal mass distribution with a significant core for the overall cluster halo, and of truncated pseudo-isothermal mass profiles for the cluster galaxies. This model is capable to predict the positions of the multiple images with an unprecedented precision of ≈ 0”.3. We also show that varying freely the cosmological parameters of the ΛCDM model, our strong lensing model can constrain the underlying geometry of the universe via the angular diameter distances between the lens and the sources and the observer and the sources.

  9. Supernova neutrinos

    SciTech Connect

    John Beacom

    2003-01-23

    We propose that neutrino-proton elastic scattering, {nu} + p {yields} {nu} + p, can be used for the detection of supernova neutrinos. Though the proton recoil kinetic energy spectrum is soft, with T{sub p} {approx_equal} 2E{sub {nu}}{sup 2}/M{sub p}, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from {bar {nu}}{sub e} + p {yields} e{sup +} + n. In addition, the measured proton spectrum is related to the incident neutrino spectrum, which solves a long-standing problem of how to separately measure the total energy release and temperature of {nu}{sub {mu}}, {nu}{sub {tau}}, {bar {nu}}{sub {mu}}, and {bar {nu}}{sub {tau}}. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.

  10. The Dark Matter filament between Abell 222/223

    NASA Astrophysics Data System (ADS)

    Dietrich, Jörg P.; Werner, Norbert; Clowe, Douglas; Finoguenov, Alexis; Kitching, Tom; Miller, Lance; Simionescu, Aurora

    2016-10-01

    Weak lensing detections and measurements of filaments have been elusive for a long time. The reason is that the low density contrast of filaments generally pushes the weak lensing signal to unobservably low scales. To nevertheless map the dark matter in filaments exquisite data and unusual systems are necessary. SuprimeCam observations of the supercluster system Abell 222/223 provided the required combination of excellent seeing images and a fortuitous alignment of the filament with the line-of-sight. This boosted the lensing signal to a detectable level and led to the first weak lensing mass measurement of a large-scale structure filament. The filament connecting Abell 222 and Abell 223 is now the only one traced by the galaxy distribution, dark matter, and X-ray emission from the hottest phase of the warm-hot intergalactic medium. The combination of these data allows us to put the first constraints on the hot gas fraction in filaments.

  11. A HIGH FIDELITY SAMPLE OF COLD FRONT CLUSTERS FROM THE CHANDRA ARCHIVE

    SciTech Connect

    Owers, Matt S.; Nulsen, Paul E. J.; Markevitch, Maxim; Couch, Warrick J.

    2009-10-20

    This paper presents a sample of 'cold front' clusters selected from the Chandra archive. The clusters are selected based purely on the existence of surface brightness edges in their Chandra images which are modeled as density jumps. A combination of the derived density and temperature jumps across the fronts is used to select nine robust examples of cold front clusters: 1ES0657 - 558, Abell 1201, Abell 1758N, MS1455.0+2232, Abell 2069, Abell 2142, Abell 2163, RXJ1720.1+2638, and Abell 3667. This sample is the subject of an ongoing study aimed at relating cold fronts to cluster merger activity, and understanding how the merging environment affects the cluster constituents. Here, temperature maps are presented along with the Chandra X-ray images. A dichotomy is found in the sample in that there exists a subsample of cold front clusters which are clearly mergers based on their X-ray morphologies, and a second subsample of clusters which harbor cold fronts, but have surprisingly relaxed X-ray morphologies, and minimal evidence for merger activity at other wavelengths. For this second subsample, the existence of a cold front provides the sole evidence for merger activity at X-ray wavelengths. We discuss how cold fronts can provide additional information which may be used to constrain merger histories, and also the possibility of using cold fronts to distinguish major and minor mergers.

  12. STRONG GRAVITATIONAL LENSING BY THE SUPER-MASSIVE cD GALAXY IN ABELL 3827

    SciTech Connect

    Carrasco, E. R.; Gomez, P. L.; Lee, H.; Diaz, R.; Bergmann, M.; Turner, J. E. H.; Miller, B. W.; West, M. J.; Verdugo, T.

    2010-06-01

    We have discovered strong gravitational lensing features in the core of the nearby cluster Abell 3827 by analyzing Gemini South GMOS images. The most prominent strong lensing feature is a highly magnified, ring-shaped configuration of four images around the central cD galaxy. GMOS spectroscopic analysis puts this source at z {approx} 0.2. Located {approx}20'' away from the central galaxy is a secondary tangential arc feature which has been identified as a background galaxy with z {approx} 0.4. We have modeled the gravitational potential of the cluster core, taking into account the mass from the cluster, the brightest cluster galaxy (BCG), and other galaxies. We derive a total mass of (2.7 {+-} 0.4) x 10{sup 13} M {sub sun} within 37 h {sup -1} kpc. This mass is an order of magnitude larger than that derived from X-ray observations. The total mass derived from lensing data suggests that the BCG in this cluster is perhaps the most massive galaxy in the nearby universe.

  13. Canibalismo Extremo y Lente Gravitacional Intensa en el Cúmulo de Galaxias Abell 3827

    NASA Astrophysics Data System (ADS)

    Díaz, R. J.; West, M.; Bergmann, M.; Carrasco, E. R.; Gomez, P.; Lee, H.; Miller, B.; Turner, J.

    Abell 3827 is one of the most massive known clusters and at its center we observe an extreme example of galactic canibalism: a super giant elliptical galaxy in its formation process, devoring five massive galaxies at the same time. Using high spatial resolution Gemini+GMOS imagery and multi-object spectroscopy, we derived the redshift (z=0.099) and the radial velocity dispersion of the 55 brightest galaxies in the cluster central region (1134 +- 125 km/s). The estimated virial mass is ~ 1E14 M(sun) inside a radius of 300 kpc of the cluster center. We have also found features corresponding to a strong gravitational lense, four anular features arranged in an Einstein Ring from a galaxy (z=0.2) at double redshift than the cluster, and a fifth arclet feature corresponding to the lensed light of a farther galaxy (z=0.4). The possible Einstein Ring is of small angular size and the gravitational lense morphology would confirm that the cluster is indeed very massive and dense. FULL TEXT IN SPANISH.

  14. Retrieval Performance and Indexing Differences in ABELL and MLAIB

    ERIC Educational Resources Information Center

    Graziano, Vince

    2012-01-01

    Searches for 117 British authors are compared in the Annual Bibliography of English Language and Literature (ABELL) and the Modern Language Association International Bibliography (MLAIB). Authors are organized by period and genre within the early modern era. The number of records for each author was subdivided by format, language of publication,…

  15. A measurement of the value of the Hubble constant from the X-ray properties and the Sunyaev-Zel'dovich effect of Abell 665

    NASA Technical Reports Server (NTRS)

    Birkinshaw, M.; Hughes, J. P.; Arnaud, K. A.

    1991-01-01

    A comparison of the X-ray properties and the Sunyaev-Zel'dovich (SZ) effect for a cluster of galaxies can be used to measure the distance of the cluster and hence the Hubble constant. This method was applied to the rich cluster Abell 665. The relative normalization of X-ray and SZ-effect data leads to an estimated Hubble constant of H sub 0 = 40 + or - 9 km/s Mpc if only the random errors are included. When the possible systematic errors are added in quadrature, the range of possible values of the Hubble constants expands to (40 to 50) + or - 12 km/s Mpc.

  16. Supernova neutrino detection

    SciTech Connect

    Scholberg, K.

    2015-07-15

    In this presentation I summarize the main detection channels for neutrinos from core-collapse supernovae, and describe current status of and future prospects for supernova-neutrino-sensitive detectors worldwide.

  17. Supernova frequency estimates

    SciTech Connect

    Tsvetkov, D.Y.

    1983-01-01

    Estimates of the frequency of type I and II supernovae occurring in galaxies of different types are derived from observational material acquired by the supernova patrol of the Shternberg Astronomical Institute.

  18. More Supernova Surprises

    DTIC Science & Technology

    2010-09-24

    SEP 2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE More Supernova Surprises 5a. CONTRACT NUMBER 5b. GRANT...PERSPECTIVES More Supernova Surprises ASTRONOMY J. Martin Laming Spectroscopic observations of the supernova SN1987A are providing a new window into high...a core-collapse supernova ) have stretched and motivated research that has expanded our knowledge of astrophysics. The brightest such event in

  19. Detection of a pair of prominent X-ray cavities in Abell 3847

    NASA Astrophysics Data System (ADS)

    Vagshette, Nilkanth D.; Naik, Sachindra; Patil, Madhav. K.; Sonkamble, Satish S.

    2017-04-01

    We present the results obtained from a detailed analysis of a deep Chandra observation of the bright FRII radio galaxy 3C 444 in Abell 3847 cluster. A pair of huge X-ray cavities are detected along the north and south directions from the centre of 3C 444. X-ray and radio images of the cluster reveal peculiar positioning of the cavities and radio bubbles. The radio lobes and X-ray cavities are apparently not spatially coincident and exhibit offsets by ∼61 and 77 kpc from each other along the north and south directions, respectively. Radial temperature and density profiles reveal the presence of a cool core in the cluster. Imaging and spectral studies showed the removal of substantial amount of matter from the core of the cluster by the radio jets. A detailed analysis of the temperature and density profiles showed the presence of a rarely detected elliptical shock in the cluster. Detection of inflating cavities at an average distance of ∼55 kpc from the centre implies that the central engine feeds a remarkable amount of radio power (∼6.3 × 1044 erg s-1) into the intra-cluster medium over ∼108 yr, the estimated age of cavity. The cooling luminosity of the cluster was estimated to be ∼8.30 × 1043 erg s-1 , which confirms that the AGN power is sufficient to quench the cooling. Ratios of mass accretion rate to Eddington and Bondi rates were estimated to be ∼0.08 and 3.5 × 104, respectively. This indicates that the black hole in the core of the cluster accretes matter through chaotic cold accretion.

  20. Disentangling the ICL with the CHEFs: Abell 2744 as a Case Study

    NASA Astrophysics Data System (ADS)

    Jiménez-Teja, Y.; Dupke, R.

    2016-03-01

    Measurements of the intracluster light (ICL) are still prone to methodological ambiguities, and there are multiple techniques in the literature to address them, mostly based on the binding energy, the local density distribution, or the surface brightness. A common issue with these methods is the a priori assumption of a number of hypotheses on either the ICL morphology, its surface brightness level, or some properties of the brightest cluster galaxy (BCG). The discrepancy in the results is high, and numerical simulations just place a boundary on the ICL fraction in present-day galaxy clusters in the range 10%-50%. We developed a new algorithm based on the Chebyshev-Fourier functions to estimate the ICL fraction without relying on any a priori assumption about the physical or geometrical characteristics of the ICL. We are able to not only disentangle the ICL from the galactic luminosity but mark out the limits of the BCG from the ICL in a natural way. We test our technique with the recently released data of the cluster Abell 2744, observed by the Frontier Fields program. The complexity of this multiple merging cluster system and the formidable depth of these images make it a challenging test case to prove the efficiency of our algorithm. We found a final ICL fraction of 19.17 ± 2.87%, which is very consistent with numerical simulations.

  1. DISENTANGLING THE ICL WITH THE CHEFs: ABELL 2744 AS A CASE STUDY

    SciTech Connect

    Jiménez-Teja, Y.; Dupke, R.

    2016-03-20

    Measurements of the intracluster light (ICL) are still prone to methodological ambiguities, and there are multiple techniques in the literature to address them, mostly based on the binding energy, the local density distribution, or the surface brightness. A common issue with these methods is the a priori assumption of a number of hypotheses on either the ICL morphology, its surface brightness level, or some properties of the brightest cluster galaxy (BCG). The discrepancy in the results is high, and numerical simulations just place a boundary on the ICL fraction in present-day galaxy clusters in the range 10%–50%. We developed a new algorithm based on the Chebyshev–Fourier functions to estimate the ICL fraction without relying on any a priori assumption about the physical or geometrical characteristics of the ICL. We are able to not only disentangle the ICL from the galactic luminosity but mark out the limits of the BCG from the ICL in a natural way. We test our technique with the recently released data of the cluster Abell 2744, observed by the Frontier Fields program. The complexity of this multiple merging cluster system and the formidable depth of these images make it a challenging test case to prove the efficiency of our algorithm. We found a final ICL fraction of 19.17 ± 2.87%, which is very consistent with numerical simulations.

  2. Condensation of dust in supernova ejecta

    NASA Astrophysics Data System (ADS)

    Sarangi, A.; Cherchneff, I.

    Observations in the infrared and submm indicate the presence of molecules and dust in the ejecta of type II-P supernovae. The mass of dust formed in the ejecta of supernovae is still uncertain and highly debated: Infrared observations indicate smaller dust masses (10-5 to 10-3 M ) before 500 days post-explosion, compared to submm observations with Herschel revealing supernova remnants as large reservoirs of cool dust (10-2 to 0.7 M ). We study the ejecta of a typical type II-P supernova with a chemical kinetic approach considering a 15 M progenitor as a benchmark. The synthesis of molecules (e.g., CO, SiO, O2, AlO, SiS, FeS, SiC, SO) and small clusters (e.g., silicates, carbon, metal oxides, metallic clusters etc.) in the gas phase is considered. The clusters form gradually over time in different ejecta zones, small dust masses form in the first 600 days (˜ 10-4 M ), that gradually increase up to ˜ 0.1 M at 1500 days post-explosion. The small clusters condense to form dust grains in the gas phase. The size distributions of different dust components are derived from the study.

  3. Abel Inversion of Deflectometric Measurements in Dynamic Flows

    NASA Technical Reports Server (NTRS)

    Agrawal, Ajay K.; Albers, Burt W.; Griffin, DeVon W.

    1999-01-01

    We present an Abel-inversion algorithm to reconstruct mean and rms refractive-index profiles from spatially resolved statistical measurements of the beam-deflection angle in time-dependent, axisymmetric flows. An oscillating gas-jet diffusion flame was investigated as a test case for applying the algorithm. Experimental data were obtained across the whole field by a rainbow schlieren apparatus. Results show that simultaneous multipoint measurements are necessary to reconstruct the rms refractive index accurately.

  4. SPECTRAL INDEX STUDIES OF THE DIFFUSE RADIO EMISSION IN ABELL 2256: IMPLICATIONS FOR MERGER ACTIVITY

    SciTech Connect

    Kale, Ruta; Dwarakanath, K. S. E-mail: dwaraka@rri.res.i

    2010-08-01

    We present a multi-wavelength analysis of the merging rich cluster of galaxies, Abell 2256 (A2256). We have observed A2256 at 150 MHz using the Giant Metrewave Radio Telescope and successfully detected the diffuse radio halo and the relic emission over a {approx}1.2 Mpc{sup 2} extent. Using this 150 MHz image and the images made using archival observations from the Very Large Array (VLA; 1369 MHz) and the Westerbrok Synthesis Radio Telescope (WSRT; 330 MHz), we have produced spectral index images of the diffuse radio emission in A2256. These spectral index images show a distribution of flat spectral index (S {proportional_to} {nu}{sup {alpha}}, {alpha} in the range -0.7 to -0.9) plasma in the region NW of the cluster center. Regions showing steep spectral indices ({alpha} in the range -1.0 to -2.3) are toward the SE of the cluster center. These spectral indices indicate synchrotron lifetimes for the relativistic plasmas in the range 0.08-0.4 Gyr. We interpret this spectral behavior as resulting from a merger event along the direction SE to NW within the last 0.5 Gyr or so. A shock may be responsible for the NW relic in A2256 and the megaparsec scale radio halo toward the SE is likely to be generated by the turbulence injected by mergers. Furthermore, the diffuse radio emission shows spectral steepening toward lower frequencies. This low-frequency spectral steepening is consistent with a combination of spectra from two populations of relativistic electrons created at two epochs (two mergers) within the last {approx}0.5 Gyr. Earlier interpretations of the X-ray and the optical data also suggested that there were two mergers in Abell 2256 in the last 0.5 Gyr, consistent with the current findings. Also highlighted in this study is the futility of correlating the average temperatures of thermal gas and the average spectral indices of diffuse radio emission in the respective clusters.

  5. The GenABEL Project for statistical genomics

    PubMed Central

    Karssen, Lennart C.; van Duijn, Cornelia M.; Aulchenko, Yurii S.

    2016-01-01

    Development of free/libre open source software is usually done by a community of people with an interest in the tool. For scientific software, however, this is less often the case. Most scientific software is written by only a few authors, often a student working on a thesis. Once the paper describing the tool has been published, the tool is no longer developed further and is left to its own device. Here we describe the broad, multidisciplinary community we formed around a set of tools for statistical genomics. The GenABEL project for statistical omics actively promotes open interdisciplinary development of statistical methodology and its implementation in efficient and user-friendly software under an open source licence. The software tools developed withing the project collectively make up the GenABEL suite, which currently consists of eleven tools. The open framework of the project actively encourages involvement of the community in all stages, from formulation of methodological ideas to application of software to specific data sets. A web forum is used to channel user questions and discussions, further promoting the use of the GenABEL suite. Developer discussions take place on a dedicated mailing list, and development is further supported by robust development practices including use of public version control, code review and continuous integration. Use of this open science model attracts contributions from users and developers outside the “core team”, facilitating agile statistical omics methodology development and fast dissemination. PMID:27347381

  6. Supernovae and mass extinctions

    NASA Technical Reports Server (NTRS)

    Vandenbergh, S.

    1994-01-01

    Shklovsky and others have suggested that some of the major extinctions in the geological record might have been triggered by explosions of nearby supernovae. The frequency of such extinction events will depend on the galactic supernova frequency and on the distance up to which a supernova explosion will produce lethal effects upon terrestrial life. In the present note it will be assumed that a killer supernova has to occur so close to Earth that it will be embedded in a young, active, supernova remnant. Such young remnants typically have radii approximately less than 3 pc (1 x 10(exp 19) cm). Larger (more pessimistic?) killer radii have been adopted by Ruderman, Romig, and by Ellis and Schramm. From observations of historical supernovae, van den Bergh finds that core-collapse (types Ib and II) supernovae occur within 4 kpc of the Sun at a rate of 0.2 plus or minus 0.1 per century. Adopting a layer thickness of 0.3 kpc for the galacitc disk, this corresponds to a rate of approximately 1.3 x 10(exp -4) supernovae pc(exp -3) g.y.(exp -1). Including supernovae of type Ia will increase the total supernovae rate to approximately 1.5 x 10(exp -4) supernovae pc(exp -3) g.y.(exp -1). For a lethal radius of R pc the rate of killer events will therefore be 1.7 (R/3)(exp 3) x 10(exp -2) supernovae per g.y. However, a frequency of a few extinctions per g.y. is required to account for the extinctions observed during the phanerozoic. With R (extinction) approximately 3 pc, the galactic supernova frequency is therefore too low by 2 orders of magnitude to account for the major extinctions in the geological record.

  7. Characterizing the Small Scale Structure in Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    Forman, William R.

    2001-01-01

    We studied galaxy clusters Abell 119, Abell 754, and Abell 1750, using data from the ASCA and ROSAT satellites. In addition, we completed the paper "Merging Binary Clusters". In this paper we study three prominent bi-modal X-ray clusters: A3528, A1750 and A3395. Since the sub-clusters in these systems have projected separations of 0.93, 1.00 and 0.67 Mpc respectively, we examine their X-ray and optical observations to investigate the dynamics and possible merging of these sub-clusters. Using data taken with ROSAT and ASCA, we analyze the temperature and surface brightness distributions. We also analyze the velocity distributions of the three clusters using new measurements supplemented with previously published data. We examined both the overall cluster properties as well as the two sub-cluster elements in each. These results were then applied to the determination of the overall cluster masses, that demonstrate excellent consistency between the various methods used. While the characteristic parameters of the sub-clusters are typical of isolated objects, our temperature results for the regions between the two sub-clusters clearly confirm the presence of merger activity that is suggested by the surface brightness distributions. These three clusters represent a progression of equal-sized sub-cluster mergers, starting from initial contact to immediately before first core passage.

  8. Supernovae neutrino pasta interaction

    NASA Astrophysics Data System (ADS)

    Lin, Zidu; Horowitz, Charles; Caplan, Matthew; Berry, Donald; Roberts, Luke

    2017-01-01

    In core-collapse supernovae, the neutron rich matter is believed to have complex structures, such as spherical, slablike, and rodlike shapes. They are collectively called ``nuclear pasta''. Supernovae neutrinos may scatter coherently on the ``nuclear pasta'' since the wavelength of the supernovae neutrinos are comparable to the nuclear pasta scale. Consequently, the neutrino pasta scattering is important to understand the neutrino opacity in the supernovae. In this work we simulated the ``nuclear pasta'' at different temperatures and densities using our semi-classical molecular dynamics and calculated the corresponding static structure factor that describes ν-pasta scattering. We found the neutrino opacities are greatly modified when the ``pasta'' exist and may have influence on the supernovae neutrino flux and average energy. Our neutrino-pasta scattering effect can finally be involved in the current supernovae simulations and we present preliminary proto neutron star cooling simulations including our pasta opacities.

  9. The Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew

    2017-01-01

    Las Cumbres Observatory is a global network of robotic telescopes specializing in time domain astronomy. It currently has nine 1m telescopes, two 2m telescopes, and seven 0.4m telescopes. The Supernova Key Project is a 3 year program to obtain light curves and spectra of 500 supernovae with Las Cumbres Observatory. Here we show recent results, detail plans for the next Supernova Key Project, and explain how the US community can get involved.

  10. Structure and Formation of cD Galaxies: NGC 6166 in ABELL 2199

    NASA Astrophysics Data System (ADS)

    Bender, Ralf; Kormendy, John; Cornell, Mark E.; Fisher, David B.

    2015-07-01

     Hobby-Eberly Telescope (HET) spectroscopy is used to measure the velocity dispersion profile of the nearest prototypical cD galaxy, NGC 6166 in the cluster Abell 2199. We also present composite surface photometry from many telescopes. We confirm the defining feature of a cD galaxy; i.e., (we suggest), a halo of stars that fills the cluster center and that is controlled dynamically by cluster gravity, not by the central galaxy. Our HET spectroscopy shows that the velocity dispersion of NGC 6166 rises from σ ≃ 300 km s-1 in the inner r˜ 10\\prime\\prime to σ =865+/- 58 km s-1 at r ˜ 100″ in the cD halo. This extends published observations of an outward σ increase and shows for the first time that σ rises all the way to the cluster velocity dispersion of 819 ± 32 km s-1. We also observe that the main body of NGC 6166 moves at +206 ± 39 km s-1 with respect to the cluster mean velocity, but the velocity of the inner cD halo is ˜70 km s-1 closer to the cluster velocity. These results support our picture that cD halos consist of stars that were stripped from individual cluster galaxies by fast tidal encounters.  However, our photometry does not confirm the widespread view that cD halos are identifiable as an extra, low-surface-brightness component that is photometrically distinct from the inner, steep-Sérsic-function main body of an otherwise-normal giant elliptical galaxy. Instead, all of the brightness profile of NGC 6166 outside its core is described to ±0.037 V mag arcsec-2 by a single Sérsic function with index n≃ 8.3. The cD halo is not recognizable from photometry alone. This blurs the distinction between cluster-dominated cD halos and the similarly-large-Sérsic-index halos of giant, core-boxy-nonrotating ellipticals. These halos are believed to be accreted onto compact, high-redshift progenitors (“red nuggets”) by large numbers of minor mergers. They belong dynamically to their central galaxies. Still, cDs and core-boxy-nonrotating Es

  11. Gamma-producing radioactivities from supernovae

    NASA Astrophysics Data System (ADS)

    Woosley, S. E.; Pinto, Philip A.

    1988-09-01

    The production of three isotopes critical to astronomical γ-ray spectroscopy, 44Ti, 56Co, and 57Co, is briefly reviewed along with the information each contains. Emphasis is placed on SN 1987A, the only Type II supernova likely to be seen in γ-lines for decases to come. The 847 keV line from 56Co decay in this supernova should peak approximately 400 days after its explosion with a flux of about 1×10-3 cm-2 s-1. For comparison, the second best candidate, a Type Ia in the Virgo cluster (20 Mpc) gives a peak flux 100 times smaller than this 100 days after the explosion. 57Co decay in SN 1987A will also present a potentially detectable signal ~1×10-4 cm-2 s-1 in 1989 through 1991. 44Ti, chiefly from Type I supernovae, is a wild card, but may be responsible for the diffuse pair background.

  12. Surviving Companions of Supernovae

    NASA Astrophysics Data System (ADS)

    Kerzendorf, W.

    2016-06-01

    Most supernovae should occur in binaries. Massive stars, the progenitors of core collapse supernovae (SN II/Ib/c), have a very high binarity fraction of 80 percent (on average, they have 1.5 companions). Binary systems are also required to produce thermonuclear supernovae (SN Ia). Understanding the role that binarity plays in pre-supernova evolution is one of the great mysteries in supernova research. Finding and studying surviving companions of supernovae has the power to shed light on some of these mysteries. Searching Galactic and nearby supernova remnants for surviving companions is a particularly powerful technique. This might allow to study the surviving companion in great detail possibly enabling a relatively detailed reconstruction of the pre-supernova evolution. In this talk, I will summarize the multitude of theoretical studies that have simulated the impact of the shockwave on the companion star and the subsequent evolution of the survivor. I will then give an overview of the searches that used these theoretical findings to identify surviving companions in nearby supernova remnants as well as their results. Finally, I will give an outlook of new opportunities in the relatively young field.

  13. Atomic and molecular supernovae

    NASA Technical Reports Server (NTRS)

    Liu, Weihong

    1997-01-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  14. SOUSA Supernova Surprises

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.

    2017-01-01

    The Swift Optical/Ultraviolet Supernova Archive is an effort to make public the Swift UVOT images and final photometry of as many supernovae as possible. These include many of the nearest, brightest, and most exciting supernovae of the last decade. Hiding within the archive, however, are supernovae you have never heard of, which never the less show extremes in color or luminosity or interesting light curve behavior in the ultraviolet. I will highlight some of the extreme objects of different subtypes and puzzling objects which warrant further study.

  15. DIFFUSE RADIO EMISSION IN ABELL 754

    SciTech Connect

    Kale, Ruta; Dwarakanath, K. S. E-mail: dwaraka@rri.res.in

    2009-07-10

    We present a low-frequency study of the diffuse radio emission in the galaxy cluster A754. We present a new 150 MHz image of the galaxy cluster A754 made with the Giant Metrewave Radio Telescope and discuss the detection of four diffuse features. We compare the 150 MHz image with the images at 74, 330, and 1363 MHz; one new diffuse feature is detected. The flux density upper limits at 330 and 1363 MHz imply a synchrotron spectral index, {alpha}>2 (S {proportional_to} {nu}{sup -{alpha}}), for the new feature. The 'west relic' detected at 74 MHz is not detected at 150 MHz and is thus consistent with its nondetection at 1363 MHz and 330 MHz. Integrated spectra of all the diffuse features are presented. The fourth diffuse feature is located along the proposed merger axis in A754 and 0.7 Mpc away from the peak of X-ray emission; we refer to it as a relic. We have made use of the framework of the adiabatic compression model to obtain spectra. We show that the spectrum of the fourth diffuse feature is consistent with that of a cocoon of a radio galaxy lurking for about 9 x 10{sup 7} yr; no shock compression is required. The other three diffuse emission have spectra steeper than 1.5 and could be cocoons lurking for longer time. We discuss other possibilities such as shocks and turbulent reacceleration being responsible for the diffuse emission in A754.

  16. A Census of Star Formation and Active Galactic Nuclei Populations in Abell 1689

    NASA Astrophysics Data System (ADS)

    Jones, Logan H.; Atlee, David Wesley

    2016-01-01

    A recent survey of low-z galaxy clusters observed a disjunction between X-ray and mid-infrared selected populations of active galactic nuclei (X-ray and IR AGNs) (Atlee+ 2011, ApJ 729, 22.). Here we present an analysis of near-infrared spectroscopic data of star-forming galaxies in cluster Abell 1689 in order to confirm the identity of some of their IR AGN and to provide a check on their reported star formation rates. Our sample consists of 24 objects in Abell 1689. H and K band spectroscopic observations of target objects and standard stars were obtained by David Atlee between 2010 May 17 and 2011 June 6 using the Large Binocular Telescope's LUCI instrument. After undergoing initial reductions, standard stars were corrected for telluric absorption using TelFit (Gullikson+ 2014, AJ, 158, 53). Raw detector counts were converted to physical units using the wavelength-dependent response of the grating and the star's reported H and K band magnitudes to produce conversion factors that fully correct for instrumental effects. Target spectra were flux-calibrated using the airmass-corrected transmission profiles produced by TelFit and the associated H band conversion factor (or the average of the two factors, for nights with two standard stars). Star formation rates were calculated using the SFR-L(Ha) relation reported in Kennicutt (1998), with the measured luminosity of the Pa-a emission line at the luminosity distance of the cluster used as a proxy for L(Ha) (Kennicutt 1998, ARA&A 36, 189; Hummer & Stoney 1987, MNRAS 346, 1055). The line ratios H2 2.121 mm/Brg and [FeII]/Pab were used to classify targets as starburst galaxies, AGNs, or LINERs (Rodriguez-Ardila+ 2005, MNRAS, 364, 1041). Jones was supported by the NOAO/KPNO Research Experience for Undergraduates (REU) Program, which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829).

  17. Type Ia Supernovae: Colors, Rates, and Progenitors

    NASA Astrophysics Data System (ADS)

    Heringer, Epson; Pritchet, Chris; Kezwer, Jason; Graham, Melissa L.; Sand, David; Bildfell, Chris

    2017-01-01

    The rate of type Ia supernovae (SNe Ia) in a galaxy depends not only on stellar mass, but also on star formation history (SFH). Here we show that two simple observational quantities (g ‑ r or u ‑ r host galaxy color, and r-band luminosity), coupled with an assumed delay time distribution (DTD) (the rate of SNe Ia as a function of time for an instantaneous burst of star formation), are sufficient to accurately determine a galaxy’s SN Ia rate, with very little sensitivity to the precise details of the SFH. Using this result, we compare observed and predicted color distributions of SN Ia hosts for the MENeaCS cluster supernova survey, and for the SDSS Stripe 82 supernova survey. The observations are consistent with a continuous DTD, without any cutoff. For old progenitor systems, the power-law slope for the DTD is found to be -{1.50}-0.15+0.19. This result favors the double degenerate scenario for SN Ia, though other interpretations are possible. We find that the late-time slopes of the DTD are different at the 1σ level for low and high stretch supernova, which suggest a single degenerate (SD) scenario for the latter. However, due to ambiguity in the current models’ DTD predictions, SD progenitors can neither be confirmed as causing high stretch supernovae nor ruled out from contributing to the overall sample.

  18. Finding Ancient Supernovae at 5 < z < 12 with Frontier Fields

    NASA Astrophysics Data System (ADS)

    Whalen, Daniel J.

    Supernovae are important probes of the properties of stars at high redshifts because they can be detected at early epochs and their masses can be inferred from their light curves. Direct detection of the first cosmic explosions in the universe will only be possible with JWST, WFIRST and the next generation of extremely large telescopes. But strong gravitational lensing by massive clusters, like those in the Frontier Fields, could reveal supernovae at slightly lower redshifts now by magnifying their flux by factors of 10 or more. We find that Frontier Fields will likely discover dozens of core-collapse supernovae at 5 < z < 12. Future surveys of cluster lenses similar in scope to Frontier Fields by JWST might find hundreds of these events out to z ~ 15 - 17. Besides revealing the masses of early stars, these ancient supernovae could also constrain cosmic star formation rates in the era of first galaxy formation.

  19. Finding Ancient Supernovae at 5 < z < 12 with Frontier Fields

    NASA Astrophysics Data System (ADS)

    Whalen, Daniel

    2015-08-01

    Supernovae are important probes of the properties of stars at high redshifts because they can be detected at early epochs and their masses can be inferred from their light curves. Finding the first cosmic explosions in the universe will only be possible with JWST, the WFIRST and the next generation of extremely large telescopes. But strong gravitational lensing by massive clusters, like those in the Frontier Fields, could reveal supernovae at slightly lower redshifts now by magnifying their flux by factors of 10 or more. We find that Frontier Fields will likely discover dozens of core-collapse supernovae at 5 < z < 12. Future surveys of cluster lenses similar in scope to Frontier Fields by JWST might find hundreds of these events out to z ~ 15 - 17. Besides revealing the masses of early stars, these ancient supernovae could also constrain cosmic star formation rates in the era of first galaxy formation.

  20. Matching Supernovae to Galaxies

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-12-01

    One of the major challenges for modern supernova surveys is identifying the galaxy that hosted each explosion. Is there an accurate and efficient way to do this that avoids investing significant human resources?Why Identify Hosts?One problem in host galaxy identification. Here, the supernova lies between two galaxies but though the centroid of the galaxy on the right is closer in angular separation, this may be a distant background galaxy that is not actually near the supernova. [Gupta et al. 2016]Supernovae are a critical tool for making cosmological predictions that help us to understand our universe. But supernova cosmology relies on accurately identifying the properties of the supernovae including their redshifts. Since spectroscopic followup of supernova detections often isnt possible, we rely on observations of the supernova host galaxies to obtain redshifts.But how do we identify which galaxy hosted a supernova? This seems like a simple problem, but there are many complicating factors a seemingly nearby galaxy could be a distant background galaxy, for instance, or a supernovas host could be too faint to spot.The authors algorithm takes into account confusion, a measure of how likely the supernova is to be mismatched. In these illustrations of low (left) and high (right) confusion, the supernova is represented by a blue star, and the green circles represent possible host galaxies. [Gupta et al. 2016]Turning to AutomationBefore the era of large supernovae surveys, searching for host galaxies was done primarily by visual inspection. But current projects like the Dark Energy Surveys Supernova Program is finding supernovae by the thousands, and the upcoming Large Synoptic Survey Telescope will likely discover hundreds of thousands. Visual inspection will not be possible in the face of this volume of data so an accurate and efficient automated method is clearly needed!To this end, a team of scientists led by Ravi Gupta (Argonne National Laboratory) has recently

  1. Bayesian Abel Inversion in Quantitative X-Ray Radiography

    SciTech Connect

    Howard, Marylesa; Fowler, Michael; Luttman, Aaron; Mitchell, Stephen E.; Hock, Margaret C.

    2016-05-19

    A common image formation process in high-energy X-ray radiography is to have a pulsed power source that emits X-rays through a scene, a scintillator that absorbs X-rays and uoresces in the visible spectrum in response to the absorbed photons, and a CCD camera that images the visible light emitted from the scintillator. The intensity image is related to areal density, and, for an object that is radially symmetric about a central axis, the Abel transform then gives the object's volumetric density. Two of the primary drawbacks to classical variational methods for Abel inversion are their sensitivity to the type and scale of regularization chosen and the lack of natural methods for quantifying the uncertainties associated with the reconstructions. In this work we cast the Abel inversion problem within a statistical framework in order to compute volumetric object densities from X-ray radiographs and to quantify uncertainties in the reconstruction. A hierarchical Bayesian model is developed with a likelihood based on a Gaussian noise model and with priors placed on the unknown density pro le, the data precision matrix, and two scale parameters. This allows the data to drive the localization of features in the reconstruction and results in a joint posterior distribution for the unknown density pro le, the prior parameters, and the spatial structure of the precision matrix. Results of the density reconstructions and pointwise uncertainty estimates are presented for both synthetic signals and real data from a U.S. Department of Energy X-ray imaging facility.

  2. Bayesian Abel Inversion in Quantitative X-Ray Radiography

    DOE PAGES

    Howard, Marylesa; Fowler, Michael; Luttman, Aaron; ...

    2016-05-19

    A common image formation process in high-energy X-ray radiography is to have a pulsed power source that emits X-rays through a scene, a scintillator that absorbs X-rays and uoresces in the visible spectrum in response to the absorbed photons, and a CCD camera that images the visible light emitted from the scintillator. The intensity image is related to areal density, and, for an object that is radially symmetric about a central axis, the Abel transform then gives the object's volumetric density. Two of the primary drawbacks to classical variational methods for Abel inversion are their sensitivity to the type andmore » scale of regularization chosen and the lack of natural methods for quantifying the uncertainties associated with the reconstructions. In this work we cast the Abel inversion problem within a statistical framework in order to compute volumetric object densities from X-ray radiographs and to quantify uncertainties in the reconstruction. A hierarchical Bayesian model is developed with a likelihood based on a Gaussian noise model and with priors placed on the unknown density pro le, the data precision matrix, and two scale parameters. This allows the data to drive the localization of features in the reconstruction and results in a joint posterior distribution for the unknown density pro le, the prior parameters, and the spatial structure of the precision matrix. Results of the density reconstructions and pointwise uncertainty estimates are presented for both synthetic signals and real data from a U.S. Department of Energy X-ray imaging facility.« less

  3. VLBA Reveals Dust-Enshrouded "Supernova Factory"

    NASA Astrophysics Data System (ADS)

    2003-05-01

    Using the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope, astronomers have discovered a newly-exploded star, or supernova, hidden deep in a dust-enshrouded "supernova factory" in a galaxy some 140 million light-years from Earth. "This supernova is likely to be part of a group of super star clusters that produce one such stellar explosion every two years," said James Ulvestad, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. "We're extremely excited by the tremendous insights into star formation and the early Universe that we may gain by observing this 'supernova factory,'" he added. Ulvestad worked with Susan Neff of NASA's Goddard Space Flight Center in Greenbelt, MD, and Stacy Teng, a graduate student at the University of Maryland, on the project. The scientists presented their findings to the American Astronomical Society's meeting in Nashville, TN. "These super star clusters likely are forming in much the same way that globular clusters formed in the early Universe, and thus provide us with a unique opportunity to learn about how some of the first stars formed billions of years ago," Neff said. The cluster is in an object called Arp 299, a pair of colliding galaxies, where regions of vigorous star formation have been found in past observations. Since 1990, four other supernova explosions have been seen optically in Arp 299. Observations with the NSF's Very Large Array (VLA) earlier showed a region near the nucleus of one of the colliding galaxies which had all the earmarks of prolific star formation. The astronomers focused on this region, prosaically dubbed "Source A," with the VLBA and the NSF's Robert C. Byrd Green Bank Telescope in 2002, and found four objects in this dusty cloud that are likely young supernova remnants. When they observed the region again in February 2003, there was a new, fifth, object located only 7 light-years from one of the previously detected objects. More observations on April 30-May

  4. HUBBLE PINPOINTS DISTANT SUPERNOVAE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These Hubble Space Telescope images pinpoint three distant supernovae, which exploded and died billions of years ago. Scientists are using these faraway light sources to estimate if the universe was expanding at a faster rate long ago and is now slowing down. Images of SN 1997cj are in the left hand column; SN 1997ce, in the middle; and SN 1997ck, on the right. All images were taken by the Hubble telescope's Wide Field and Planetary Camera 2. The top row of images are wider views of the supernovae. The supernovae were discovered in April 1997 in a ground-based survey at the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii. Once the supernovae were discovered, the Hubble telescope was used to distinguish the supernovae from the light of their host galaxies. A series of Hubble telescope images were taken in May and June 1997 as the supernovae faded. Six Hubble telescope observations spanning five weeks were taken for each supernova. This time series enabled scientists to measure the brightness and create a light curve. Scientists then used the light curve to make an accurate estimate of the distances to the supernovae. Scientists combined the estimated distance with the measured velocity of the supernova's host galaxy to determine the expansion rate of the universe in the past (5 to 7 billion years ago) and compare it with the current rate. These supernovae belong to a class called Type Ia, which are considered reliable distance indicators. Looking at great distances also means looking back in time because of the finite velocity of light. SN 1997ck exploded when the universe was half its present age. It is the most distant supernova ever discovered (at a redshift of 0.97), erupting 7.7 billion years ago. The two other supernovae exploded about 5 billion years ago. SN 1997ce has a redshift of 0.44; SN 1997cj, 0.50. SN 1997ck is in the constellation Hercules, SN 1997ce is in Lynx, just north of Gemini; and SN 1997cj is in Ursa Major, near the Hubble Deep Field

  5. VizieR Online Data Catalog: Brightest cluster galaxies in Abell clusters (Lauer+, 2014)

    NASA Astrophysics Data System (ADS)

    Lauer, T. R.; Postman, M.; Strauss, M. A.; Graves, G. J.; Chisari, N. E.

    2017-01-01

    Images of the BCGs were obtained in 13 runs between 1989 and 1995 using CCD cameras on the Kitt Peak National Observatory (KPNO) 4m, KPNO 2.1m, and Cerro Tololo Inter-American Observatory (CTIO) 1.5m telescopes.We obtained long-slit spectra of all BCG candidates in the sample over the course of 14 observing runs, spanning a 5yr timeframe, at NOAO's CTIO and KPNO. The CTIO observations were done primarily using the Blanco 4m Telescope, except for the first two runs, which used the 1.5m telescope. All KPNO runs were done using the Goldcam spectrograph on the 2.1m telescope. (5 data files).

  6. The Noble-Abel Stiffened-Gas equation of state

    NASA Astrophysics Data System (ADS)

    Le Métayer, Olivier; Saurel, Richard

    2016-04-01

    Hyperbolic two-phase flow models have shown excellent ability for the resolution of a wide range of applications ranging from interfacial flows to fluid mixtures with several velocities. These models account for waves propagation (acoustic and convective) and consist in hyperbolic systems of partial differential equations. In this context, each phase is compressible and needs an appropriate convex equation of state (EOS). The EOS must be simple enough for intensive computations as well as boundary conditions treatment. It must also be accurate, this being challenging with respect to simplicity. In the present approach, each fluid is governed by a novel EOS named "Noble Abel stiffened gas," this formulation being a significant improvement of the popular "Stiffened Gas (SG)" EOS. It is a combination of the so-called "Noble-Abel" and "stiffened gas" equations of state that adds repulsive effects to the SG formulation. The determination of the various thermodynamic functions and associated coefficients is the aim of this article. We first use thermodynamic considerations to determine the different state functions such as the specific internal energy, enthalpy, and entropy. Then we propose to determine the associated coefficients for a liquid in the presence of its vapor. The EOS parameters are determined from experimental saturation curves. Some examples of liquid-vapor fluids are examined and associated parameters are computed with the help of the present method. Comparisons between analytical and experimental saturation curves show very good agreement for wide ranges of temperature for both liquid and vapor.

  7. Ionospheric electron density inversion for Global Navigation Satellite Systems radio occultation using aided Abel inversions

    NASA Astrophysics Data System (ADS)

    Chou, Min Yang; Lin, Charles C. H.; Tsai, Ho Fang; Lin, Chi Yen

    2017-01-01

    The Abel inversion of ionospheric electron density profiles with the assumption of spherical symmetry applied for radio occultation soundings could introduce a greater systematic error or sometimes artifacts if the occultation rays trespass regions with larger horizontal gradients in electron density. The aided Abel inversions have been proposed by considering the asymmetry ratio derived from ionospheric total electron content (TEC) or peak density (NmF2) of reconstructed observation maps since knowledge of the horizontal asymmetry in ambient ionospheric density could mitigate the inversion error. Here we propose a new aided Abel inversion using three-dimensional time-dependent electron density (Ne) based on the climatological maps constructed from previous observations, as it has an advantage of providing altitudinal information on the horizontal asymmetry. Improvement of proposed Ne-aided Abel inversion and comparisons with electron density profiles inverted from the NmF2- and TEC-aided inversions are studied using observation system simulation experiments. Comparison results show that all three aided Abel inversions improve the ionospheric profiling by mitigating the artificial plasma caves and negative electron density in the daytime E region. The equatorial ionization anomaly crests in the F region become more distinct. The statistical results show that the Ne-aided Abel inversion has less mean and RMS error of error percentage above 250 km altitudes, and the performances for all aided Abel inversions are similar below 250 km altitudes.

  8. Galaxy Zoo Supernovae

    NASA Astrophysics Data System (ADS)

    Smith, A. M.; Lynn, S.; Sullivan, M.; Lintott, C. J.; Nugent, P. E.; Botyanszki, J.; Kasliwal, M.; Quimby, R.; Bamford, S. P.; Fortson, L. F.; Schawinski, K.; Hook, I.; Blake, S.; Podsiadlowski, P.; Jönsson, J.; Gal-Yam, A.; Arcavi, I.; Howell, D. A.; Bloom, J. S.; Jacobsen, J.; Kulkarni, S. R.; Law, N. M.; Ofek, E. O.; Walters, R.

    2011-04-01

    This paper presents the first results from a new citizen science project: Galaxy Zoo Supernovae. This proof-of-concept project uses members of the public to identify supernova candidates from the latest generation of wide-field imaging transient surveys. We describe the Galaxy Zoo Supernovae operations and scoring model, and demonstrate the effectiveness of this novel method using imaging data and transients from the Palomar Transient Factory (PTF). We examine the results collected over the period 2010 April-July, during which nearly 14 000 supernova candidates from the PTF were classified by more than 2500 individuals within a few hours of data collection. We compare the transients selected by the citizen scientists to those identified by experienced PTF scanners and find the agreement to be remarkable - Galaxy Zoo Supernovae performs comparably to the PTF scanners and identified as transients 93 per cent of the ˜130 spectroscopically confirmed supernovae (SNe) that the PTF located during the trial period (with no false positive identifications). Further analysis shows that only a small fraction of the lowest signal-to-noise ratio detections (r > 19.5) are given low scores: Galaxy Zoo Supernovae correctly identifies all SNe with ≥8σ detections in the PTF imaging data. The Galaxy Zoo Supernovae project has direct applicability to future transient searches, such as the Large Synoptic Survey Telescope, by both rapidly identifying candidate transient events and via the training and improvement of existing machine classifier algorithms. This publication has been made possible by the participation of more than 10 000 volunteers in the Galaxy Zoo Supernovae project ().

  9. Neutrinos and Supernovae

    SciTech Connect

    Meyer, Bradley S.

    2008-05-12

    Core-collapse supernovae are one of the few astrophysical environments in which neutrinos play a dominant role. Neutrinos emission is the means by which a newly-born neutron star formed in a core-collapse event cools. Neutrinos may play a significant role in causing the supernova explosion. Finally neutrinos may significantly affect the nucleosynthesis occurring in the layers of the exploding star that are eventually ejected into interstellar space. This paper reviews some interesting neutrino-nucleus processes that may occur in the cores of exploding massive stars and then discusses some effects neutrinos may have on explosive nucleosynthesis in supernovae.

  10. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect

    Claudia, Travaglio; Hix, William Raphael

    2013-01-01

    We review our understanding of the nucleosynthesis that occurs in thermonuclear supernovae and their contribution to Galactic Chemical evolution. We discuss the prospects to improve the modeling of the nucleosynthesis within simulations of these events.

  11. Supernovae, neutrinos, and nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Fröhlich, Carla

    2014-04-01

    Core-collapse supernovae are the violent explosions at the end of the life of massive stars (≳ 8 - 10 M⊙). In these explosions a wide range of elements are synthesized and ejected: low-mass elements (O and Mg) from the hydrostatic evolution, intermediate-mass elements and Fe-group elements from explosive nucleosynthesis, and elements heavier than iron from the νp-process and potentially an r-process. However, supernova nucleosynthesis predictions are hampered by the not yet fully understood supernova explosion mechanism. In addition, recent progress in observational astronomy paints a fascinating picture for the origin of heavy elements, which is more complicated than the traditional s-, r-, and γ-processes. In this paper, we summarize the status of core-collapse supernova nucleosynthesis.

  12. Berkeley automated supernova search

    SciTech Connect

    Kare, J.T.; Pennypacker, C.R.; Muller, R.A.; Mast, T.S.; Crawford, F.S.; Burns, M.S.

    1981-01-01

    The Berkeley automated supernova search employs a computer controlled 36-inch telescope and charge coupled device (CCD) detector to image 2500 galaxies per night. A dedicated minicomputer compares each galaxy image with stored reference data to identify supernovae in real time. The threshold for detection is m/sub v/ = 18.8. We plan to monitor roughly 500 galaxies in Virgo and closer every night, and an additional 6000 galaxies out to 70 Mpc on a three night cycle. This should yield very early detection of several supernovae per year for detailed study, and reliable premaximum detection of roughly 100 supernovae per year for statistical studies. The search should be operational in mid-1982.

  13. Automated search for supernovae

    SciTech Connect

    Kare, J.T.

    1984-11-15

    This thesis describes the design, development, and testing of a search system for supernovae, based on the use of current computer and detector technology. This search uses a computer-controlled telescope and charge coupled device (CCD) detector to collect images of hundreds of galaxies per night of observation, and a dedicated minicomputer to process these images in real time. The system is now collecting test images of up to several hundred fields per night, with a sensitivity corresponding to a limiting magnitude (visual) of 17. At full speed and sensitivity, the search will examine some 6000 galaxies every three nights, with a limiting magnitude of 18 or fainter, yielding roughly two supernovae per week (assuming one supernova per galaxy per 50 years) at 5 to 50 percent of maximum light. An additional 500 nearby galaxies will be searched every night, to locate about 10 supernovae per year at one or two percent of maximum light, within hours of the initial explosion.

  14. Supernova feedback in molecular clouds: global evolution and dynamics

    NASA Astrophysics Data System (ADS)

    Körtgen, Bastian; Seifried, Daniel; Banerjee, Robi; Vázquez-Semadeni, Enrique; Zamora-Avilés, Manuel

    2016-07-01

    We use magnetohydrodynamical simulations of converging warm neutral medium flows to analyse the formation and global evolution of magnetized and turbulent molecular clouds subject to supernova feedback from massive stars. We show that supernova feedback alone fails to disrupt entire, gravitationally bound, molecular clouds, but is able to disperse small-sized (˜10 pc) regions on time-scales of less than 1 Myr. Efficient radiative cooling of the supernova remnant as well as strong compression of the surrounding gas result in non-persistent energy and momentum input from the supernovae. However, if the time between subsequent supernovae is short and they are clustered, large hot bubbles form that disperse larger regions of the parental cloud. On longer time-scales, supernova feedback increases the amount of gas with moderate temperatures (T ≈ 300-3000 K). Despite its inability to disrupt molecular clouds, supernova feedback leaves a strong imprint on the star formation process. We find an overall reduction of the star formation efficiency by a factor of 2 and of the star formation rate by roughly factors of 2-4.

  15. Handbook of Supernovae

    NASA Astrophysics Data System (ADS)

    Athem Alsabti, Abdul

    2015-08-01

    Since the discovery of pulsars in 1967, few celestial phenomena have fascinated amateur and professional astronomers, and the public, more than supernovae - dying stars that explode spectacularly and, in so doing, may outshine a whole galaxy. Thousands of research papers, reviews, monographs and books have been published on this subject. These publications are often written either for a highly specific level of expertise or education, or with respect to a particular aspect of supernovae research. However, the study of supernovae is a very broad topic involving many integral yet connected aspects, including physics, mathematics, computation, history, theoretical studies and observation. More specifically, areas of study include historical supernovae, the different types and light curves, nucleosynthesis, explosion mechanisms, formation of black holes, neutron stars, cosmic rays, neutrinos and gravitational waves. Related questions include how supernovae remnants interact with interstellar matter nearby and how do these events affect the formation of new stars or planetary systems? Could they affect existing planetary systems? Closer to home, did any supernovae affect life on earth in the past or could they do so in the future? And on the larger scale, how did supernovae observations help measure the size and expansion of the universe? All these topics, and more, are to be covered in a new reference work, consisting of more than 100 articles and more than 1700 pages. It is intended to cover all the main facets of current supernovae research. It will be pitched at or above the level of a new postgraduate student, who will have successfully studied physics (or a similar scientific subject) to Bachelor degree level. It will be available in both print and electronic (updatable) formats, with the exception of the first section, which will consist of a review of all the topics of the handbook at a level that allows anyone with basic scientific knowledge to grasp the

  16. Supernova 1987A

    NASA Astrophysics Data System (ADS)

    McCray, R.; Murdin, P.

    2002-10-01

    Supernova 1987A (SN1987A) in the LARGE MAGELLANIC CLOUD (LMC) is the brightest supernova to be observed since SN1604 (Kepler), the first to be observed in every band of the ELECTROMAGNETIC SPECTRUM and the first to be detected through its initial burst of NEUTRINOS. Although the bolometric luminosity of SN1987A today is ≈10-6 of its value at maximum light (Lmax≈2.5×108L⊙), it ...

  17. Dust in supernova remnants

    NASA Astrophysics Data System (ADS)

    Gomez, H.

    In this Review, I will discuss our changing view on supernovae as interstellar dust sources. In particular I will focus on infrared and submillimetre studies of the historical supernova remnants Cassiopeia A, the Crab Nebula, SN 1987A, Tycho and Kepler. In the last decade (and particularly in recent years), SCUBA, Herschel and ALMA have now demonstrated that core-collapse supernovae are prolific dust factories, with evidence of 0.1 - 0.7 M⊙ of dust formed in the ejecta, though there is little evidence (as yet) for significant dust production in Type Ia supernova ejecta. There is no longer any question that dust (and molecule) formation is efficient after some supernova events, though it is not clear how much of this will survive over longer timescales. Current and future instruments will allow us to investigate the spatial distribution of dust within corecollapse ejecta, and whether this component contributes a significant amount to the dust content of the Universe or if supernovae ultimately provide a net loss once dust destruction by shocks is taken into account.

  18. Neutrinos from supernovae.

    NASA Astrophysics Data System (ADS)

    Burrows, A. S.

    First, the author presents a short history of supernova neutrino theory. Then, the theory of core collapse supernovae is reviewed. Because of the profound opacity to light of the dense core that experiences collapse, we "see" this core directly only through its neutrino signature. Every bump and wiggle echoes the internal convulsions of the event and can provide clues about both the supernova mechanism and the neutron star that remains. The author discusses the only neutrino observations of a supernova so far, SN 1987A. While the agreement with calculations has been gratifying, there remain, of course, plenty of outstanding issues in supernova theory to be tested. These are high-lighted throughout the text. Since neutrinos give us the only real access to the physics inside the collapse, it is important that observation of these particles continue. In an appendix the author describes some of the available or contemplated neutrino detectors capable of good time resolution and therefore of shedding light on supernova mechanisms.

  19. Quintuplet Cluster

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Penetrating 25,000 light-years of obscuring dust and myriad stars, NASA's Hubble Space Telescope has provided the clearest view yet of one of the largest young clusters of stars inside our Milky Way galaxy, located less than 100 light-years from the very center of the Galaxy. Having the equivalent mass greater than 10,000 stars like our sun, the monster cluster is ten times larger than typical young star clusters scattered throughout our Milky Way. It is destined to be ripped apart in just a few million years by gravitational tidal forces in the galaxy's core. But in its brief lifetime it shines more brightly than any other star cluster in the Galaxy. Quintuplet Cluster is 4 million years old. It has stars on the verge of blowing up as supernovae. It is the home of the brightest star seen in the galaxy, called the Pistol star. This image was taken in infrared light by Hubble's NICMOS camera in September 1997. The false colors correspond to infrared wavelengths. The galactic center stars are white, the red stars are enshrouded in dust or behind dust, and the blue stars are foreground stars between us and the Milky Way's center. The cluster is hidden from direct view behind black dust clouds in the constellation Sagittarius. If the cluster could be seen from earth it would appear to the naked eye as a 3rd magnitude star, 1/6th of a full moon's diameter apart.

  20. DISCOVERY OF ULTRA-STEEP SPECTRUM GIANT RADIO GALAXY WITH RECURRENT RADIO JET ACTIVITY IN ABELL 449

    SciTech Connect

    Hunik, Dominika; Jamrozy, Marek

    2016-01-20

    We report a discovery of a 1.3 Mpc diffuse radio source with extremely steep spectrum fading radio structures in the vicinity of the Abell 449 cluster of galaxies. Its extended diffuse lobes are bright only at low radio frequencies and their synchrotron age is about 160 Myr. The parent galaxy of the extended relic structure, which is the dominant galaxy within the cluster, is starting a new jet activity. There are three weak X-rays sources in the vicinity of the cluster as found in the ROSAT survey, however it is not known if they are connected with this cluster of galaxies. Just a few radio galaxy relics are currently known in the literature, as finding them requires sensitive and high angular resolution low-frequency radio observations. Objects of this kind, which also are starting a new jet activity, are important for understanding the life cycle and evolution of active galactic nuclei. A new 613 MHz map as well as the archival radio data pertaining to this object are presented and analyzed.

  1. Brig. Gen. Richard F. Abel and Col. Natan J. Lindsay answering questions

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Brigadier General Richard F. Abel, right, director of public affairs for the Air Force, and Colonel Nathan J. Lindsay of the USAF's space division, answer questions concerning STS-4 during a press conference at JSC on May 20, 1982.

  2. Comparison of four stable numerical methods for Abel's integral equation

    NASA Technical Reports Server (NTRS)

    Murio, Diego A.; Mejia, Carlos E.

    1991-01-01

    The 3-D image reconstruction from cone-beam projections in computerized tomography leads naturally, in the case of radial symmetry, to the study of Abel-type integral equations. If the experimental information is obtained from measured data, on a discrete set of points, special methods are needed in order to restore continuity with respect to the data. A new combined Regularized-Adjoint-Conjugate Gradient algorithm, together with two different implementations of the Mollification Method (one based on a data filtering technique and the other on the mollification of the kernal function) and a regularization by truncation method (initially proposed for 2-D ray sample schemes and more recently extended to 3-D cone-beam image reconstruction) are extensively tested and compared for accuracy and numerical stability as functions of the level of noise in the data.

  3. ABEL description and implementation of cyber net system

    NASA Astrophysics Data System (ADS)

    Lu, Jiyuan; Jing, Liang

    2013-03-01

    Cyber net system is a subclass of Petri Nets. It has more powerful description capability and more complex properties compared with P/T system. Due to its nonlinear relation, it can't use analysis techniques of other net systems directly. This influences the research on cyber net system. In this paper, the author uses hardware description language to describe cyber net system. Simulation analysis is carried out through EDA software tools to disclose properties of the system. This method is introduced in detail through cyber net system model of computing Fibonacci series. ABEL source codes and simulation wave are also presented. The source codes are compiled, optimized, fit design and downloaded to the Programmable Logic Device. Thus ASIC of computing Fibonacci series is obtained. It will break a new path for the analysis and application study of cyber net system.

  4. PROGENITORS OF RECOMBINING SUPERNOVA REMNANTS

    SciTech Connect

    Moriya, Takashi J.

    2012-05-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

  5. Galaxy Clusters in the Swift/BAT era II: 10 more Clusters detected above 15 keV

    SciTech Connect

    Ajello, M.; Rebusco, P.; Cappelluti, N.; Reimer, O.; Boehringer, H.; La Parola, V.; Cusumano, G.; /Palermo Observ.

    2010-10-27

    We report on the discovery of 10 additional galaxy clusters detected in the ongoing Swift/BAT all-sky survey. Among the newly BAT-discovered clusters there are: Bullet, Abell 85, Norma, and PKS 0745-19. Norma is the only cluster, among those presented here, which is resolved by BAT. For all the clusters we perform a detailed spectral analysis using XMM-Newton and Swift/BAT data to investigate the presence of a hard (non-thermal) X-ray excess. We find that in most cases the clusters emission in the 0.3-200 keV band can be explained by a multi-temperature thermal model confirming our previous results. For two clusters (Bullet and Abell 3667) we find evidence for the presence of a hard X-ray excess. In the case of the Bullet cluster, our analysis confirms the presence of a non-thermal, power-law like, component with a 20-100 keV flux of 3.4 x 10{sup -12} erg cm{sup -2} s{sup -1} as detected in previous studies. For Abell 3667 the excess emission can be successfully modeled as a hot component (kT = {approx}13 keV). We thus conclude that the hard X-ray emission from galaxy clusters (except the Bullet) has most likely thermal origin.

  6. On the Likelihood of Supernova Enrichment of Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Williams, Jonathan P.; Gaidos, Eric

    2007-07-01

    We estimate the likelihood of direct injection of supernova ejecta into protoplanetary disks using a model in which the number of stars with disks decreases linearly with time, and clusters expand linearly with time such that their surface density is independent of stellar number. The similarity of disk dissipation and main-sequence lifetimes implies that the typical supernova progenitor is very massive, ~75-100 Msolar. Such massive stars are found only in clusters with >~104 members. Moreover, there is only a small region around a supernova within which disks can survive the blast yet be enriched to the level observed in the solar system. These two factors limit the overall likelihood of supernova enrichment of a protoplanetary disk to <~1%. If the presence of short-lived radionucleides in meteorites is to be explained in this way, however, the solar system most likely formed in one of the largest clusters in the Galaxy, more than 2 orders of magnitude greater than Orion, where multiple supernovae impacted many disks in a short period of time.

  7. GHRS observations of mass-loaded flows in Abell 78

    NASA Technical Reports Server (NTRS)

    Harrington, J. Patrick; Borkowski, Kazimierz J.; Tsvetanov, Zlatan

    1995-01-01

    Spectroscopic observations of the central star of the planetary nebula Abell 78 were obtained with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope (HST) in the vicinity of the C IV lambda 1548.2, 1550.8 doublet. We find a series of narrow absorption features superposed on the broad, P Cygni stellar wind profile. These features are seen in both components of the doublet at heliocentric radial velocities of -18, -71, -131, and -192 km/s. At higher velocities, individual components are no longer distinct but, rather, merge into a continuous absorption extending to approximately -385 km/s. This is among the highest velocities ever detected for gas in a planetary nebula. The -18 km/s feature originates in an outer envelope of normal composition, while the -71 km/s feature is produced in the wind-swept shell encircling an irregular wind-blown bubble in the planetary nebula center. The hydrogen-poor ejecta of Abell 78, consisting of dense knots with wind-blown tails, are located in the bubble's interior, in the vicinity of the stellar wind termination shock. The high-velocity C IV lambda 154 absorption features can be explained as due to parcels of ejecta being accelerated to high velocities as they are swept up by the stellar wind during its interaction with dense condensations of H-poor ejecta. As the ablated material is accelerated, it will partially mix with the stellar wind, creating a mass-loaded flow. The abundance anomalies seen at the rim of the bubble attest to the transport of H-poor knot material by such a flow.

  8. Coma cluster of galaxies

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

  9. Disentangling the ICL with the CHEFs: Abell 2744 as a case study

    NASA Astrophysics Data System (ADS)

    Jimenez-Teja, Yolanda; Dupke, Renato a.

    2015-08-01

    The intracluster light (ICL) is important for understanding the metal enrichment of the intracluster gas and constraining cosmological parameters independently of the other methods. However, its measurement it is not trivial due to the necessity of disentangling the light of stars locked up in galaxies from the proper ICL. Currently, there is no standard method to efficiently measure the ICL (Rudick et al. 2011, ApJ, 732, 48), and different approaches relying on the binding energy of the cluster galaxies, the density of the material, or the surface brightness distribution, have been tried. Moreover, a suitable way to disentangle the limits of the brightest cluster galaxy (BCG) and the ICL still has not been developed.The CHEFs (from Chebyshev-Fourier bases, Jiménez-Teja & Benítez 2012, ApJ, 745, 150) are a mathematical tool especially designed to model the two-dimensional light distribution of galaxies. We use the CHEFs and tools from differential geometry to infer the light contribution of the ICL to the total brightness, without imposing any artificial thresholds and avoiding the ambiguity introduced by free parameters that are usually set in these studies (Rudick et al. 2011).We use the extremely deep optical images from Abell 2744, the Pandora cluster, a multi-cluster merger, observed by the Hubble Frontier Fields project to show the efficiency of this new method. The CHEFs can accurately fit and remove all the galaxies close to the cluster center, including the BCG. The limits of the BCG are marked out by determining the points where the surface curvature changes, thus disentangling the ICL from the BCG light in a completely natural way. Once we have the residual image just containing ICL and background, we extrapolate the value of this latter from images of individual pointings close to the main Pandora field. We finally estimate the ICL to be ~24% of the total light, which is very consistent with the predictions from numerical simulations (Montes

  10. An analysis of the halo and relic radio emission from Abell 3376 from Murchison Widefield Array observations

    NASA Astrophysics Data System (ADS)

    George, L. T.; Dwarakanath, K. S.; Johnston-Hollitt, M.; Hurley-Walker, N.; Hindson, L.; Kapińska, A. D.; Tingay, S. J.; Bell, M.; Callingham, J. R.; For, Bi-Qing; Hancock, P. J.; Lenc, E.; McKinley, B.; Morgan, J.; Offringa, A.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, Chen; Zheng, Q.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Emrich, D.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Kaplan, D. L.; Kasper, J. C.; Kratzenberg, E.; Lonsdale, C. J.; Lynch, M. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Waterson, M.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.

    2015-08-01

    We have carried out multiwavelength observations of the nearby (z = 0.046) rich, merging galaxy cluster Abell 3376 with the Murchison Widefield Array (MWA). As a part of the GaLactic and Extragalactic All-sky MWA Survey, this cluster was observed at 88, 118, 154, 188, and 215 MHz. The known radio relics, towards the eastern and western peripheries of the cluster, were detected at all the frequencies. The relics, with a linear extent of ˜1 Mpc each, are separated by ˜2 Mpc. Combining the current observations with those in the literature, we have obtained the spectra of these relics over the frequency range 80-1400 MHz. The spectra follow power laws, with α = -1.17 ± 0.06 and -1.37 ± 0.08 for the west and east relics, respectively (S∝να). Assuming the break frequency to be near the lower end of the spectrum we estimate the age of the relics to be ˜0.4 Gyr. No diffuse radio emission from the central regions of the cluster (halo) was detected. The upper limit on the radio power of any possible halo that might be present in the cluster is a factor of 35 lower than that expected from the radio power and X-ray luminosity correlation for cluster haloes. From this we conclude that the cluster halo is very extended (>500 kpc) and/or most of the radio emission from the halo has decayed. The current limit on the halo radio power is a factor of 10 lower than the existing upper limits with possible implications for models of halo formation.

  11. Modeling Core Collapse Supernovae

    NASA Astrophysics Data System (ADS)

    Mezzacappa, Anthony

    2017-01-01

    Core collapse supernovae, or the death throes of massive stars, are general relativistic, neutrino-magneto-hydrodynamic events. The core collapse supernova mechanism is still not in hand, though key components have been illuminated, and the potential for multiple mechanisms for different progenitors exists. Core collapse supernovae are the single most important source of elements in the Universe, and serve other critical roles in galactic chemical and thermal evolution, the birth of neutron stars, pulsars, and stellar mass black holes, the production of a subclass of gamma-ray bursts, and as potential cosmic laboratories for fundamental nuclear and particle physics. Given this, the so called ``supernova problem'' is one of the most important unsolved problems in astrophysics. It has been fifty years since the first numerical simulations of core collapse supernovae were performed. Progress in the past decade, and especially within the past five years, has been exponential, yet much work remains. Spherically symmetric simulations over nearly four decades laid the foundation for this progress. Two-dimensional modeling that assumes axial symmetry is maturing. And three-dimensional modeling, while in its infancy, has begun in earnest. I will present some of the recent work from the ``Oak Ridge'' group, and will discuss this work in the context of the broader work by other researchers in the field. I will then point to future requirements and challenges. Connections with other experimental, observational, and theoretical efforts will be discussed, as well.

  12. Three-point correlations of galaxy clusters

    NASA Technical Reports Server (NTRS)

    Toth, Gabor; Hollosi, Joseph; Szalay, Alexander S.

    1989-01-01

    A relation between two- and three-point correlation functions similar to that of galaxies is presently established by estimating the irreducible angular three-point correlation function of Abell clusters in distance classes 5 and 6, for Galactic latitudes below 40 deg. The shape of the three-point correlation function is fully consistent with the quadratic scaling law found by Groth and Peebles (1977) for galaxies. The three-point correlation function is inconsistent with the expectations from biasing.

  13. Supernovae by the Hundreds: the LCOGT Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis; Valenti, Stefano; LCOGT Key Project

    2016-01-01

    The LCOGT Supernova Key Project is a three year project to obtain lightcurves and spectra of 600 supernovae. To do this, it has been awarded 2900 hours per year on the 9 one meter and 2 two meter robotic telescopes of the Las Cumbres Observatory Global Telescope network (LCOGT). At the midway point of the Key Project, it is on track to achieving its goals. I will discuss recent insights into supernova progenitors, exotic individual supernovae, and some of the large samples of supernovae studied by the project.

  14. A Double Lobe Radio Galaxy Between Clusters: Constraints on the Intrafilament Medium Density

    NASA Astrophysics Data System (ADS)

    Edwards, Louise O. V.; Fadda, D.; Frayer, D. T.

    2011-01-01

    We have found the first bent double lobe radio source (DLRS) in a known cluster filament. This discovery has enabled us to constrain the intrafilament density (IFM) to be between (1-10)x10-29 gm/cm3. The host filament has been observed using extensive multiwavelength photometry and confirmed with hundreds of member redshifts. It stretches from the rich galaxy cluster Abell 1763 to the nearby cluster Abell 1770, 13Mpc away. Our recent observations from the VLA uncovered the DLRS at a distance of 3.4Mpc from the center of Abell 1763, well outside the virial radius of either cluster. We measure the jet flux and calculate the minimum pressure in the jet. Using geometric arguments to derive the orientation and bend of the jet, and assuming that the bend of the of the jet is due to ram pressure, we are able to constraint the density of the IFM. Our measurements agree with the small number of IFM estimates that currently exist, including results from different approaches such as the direct X-ray observations of Abell 222/223 and related WHIM measurements in Sculptor, as well as theoretical models. Our findings justify future searches for bent double lobe radio sources located several Mpc from cluster cores, as they may be good markers of super cluster filaments.

  15. Supernova and cosmic rays

    NASA Technical Reports Server (NTRS)

    Wefel, J. P.

    1981-01-01

    A general overview of supernova astronomy is presented, followed by a discussion of the relationship between SN and galactic cosmic rays. Pre-supernova evolution is traced to core collapse, explosion, and mass ejection. The two types of SN light curves are discussed in terms of their causes, and the different nucleosynthetic processes inside SNs are reviewed. Physical events in SN remnants are discussed. The three main connections between cosmic rays and SNs, the energy requirement, the acceleration mechanism, and the detailed composition of CR, are detailed.

  16. The WFIRST Supernova Survey

    NASA Astrophysics Data System (ADS)

    Foley, Ryan J.; Hounsell, Rebekah; Scolnic, Daniel; WFIRST Supernova Science Investigation Team

    2017-01-01

    WFRIST is expected to launch in the mid 2020s. As part of its main mission, it will conduct a survey to measure the Universe's cosmic expansion history with supernovae. I will present the first simulations of this survey. The simulations take into account our current knowledge of the hardware, realistic properties of the supernovae, and our understanding of the relevant systematic uncertainties. I will compare the ultimate dark enegery figures of merit derived from the simulations and discuss future plans. These data will be extremely useful for other science; other transient science and studies of the resulting deep static images will particularly benefit.

  17. Demonstrating Supernova Remnant Evolution

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Williams, Jacqueline

    2017-01-01

    We have created a software tool to calculate at display supernova remnant evolution which includes all stages from early ejecta dominated phase to late-time merging with the interstellar medium. The software was created using Python, and can be distributed as Python code, or as an executable file. The purpose of the software is to demonstrate the different phases and transitions that a supernova remnant undergoes, and will be used in upper level undergraduate astrophysics courses as a teaching tool. The usage of the software and its graphical user interface will be demonstrated.

  18. Supernova 1987A

    NASA Technical Reports Server (NTRS)

    Mccray, Richard; Li, Hong Wei

    1988-01-01

    Supernova 1987A (February 23, 1987) in the Large Magellanic Cloud is the brightest supernova to be observed since SN 1604 AD (Kepler). Detection of a burst of neutrinos indicates that a neutron star was formed. Radioactive decay of about 0.07 solar mass of Co-56 is responsible for the observed optical light as well as hard X-rays and gamma-ray lines. Ultraviolet, optical, and infrared 'light echoes' and soft X-rays provide information on the distribution of circumstellar matter and the evolution of the progenitor star.

  19. What Shapes Supernova Remnants?

    NASA Astrophysics Data System (ADS)

    Lopez, Laura A.

    2014-01-01

    Evidence has mounted that Type Ia and core-collapse (CC) supernovae (SNe) can have substantial deviations from spherical symmetry; one such piece of evidence is the complex morphologies of supernova remnants (SNRs). However, the relative role of the explosion geometry and the environment in shaping SNRs remains an outstanding question. Recently, we have developed techniques to quantify the morphologies of SNRs, and we have applied these methods to the extensive X-ray and infrared archival images available of Milky Way and Magellanic Cloud SNRs. In this proceeding, we highlight some results from these studies, with particular emphasis on SNR asymmetries and whether they arise from ``nature'' or ``nurture''.

  20. The APM Galaxy Survey - V. Catalogues of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Dalton, G. B.; Maddox, S. J.; Sutherland, W. J.; Efstathiou, G.

    1997-08-01

    We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing them with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters.

  1. The planetary nebula Abell 48 and its [WN] nucleus

    NASA Astrophysics Data System (ADS)

    Frew, David J.; Bojičić, I. S.; Parker, Q. A.; Stupar, M.; Wachter, S.; DePew, K.; Danehkar, A.; Fitzgerald, M. T.; Douchin, D.

    2014-05-01

    We have conducted a detailed multi-wavelength study of the peculiar nebula Abell 48 and its central star. We classify the nucleus as a helium-rich, hydrogen-deficient star of type [WN4-5]. The evidence for either a massive WN or a low-mass [WN] interpretation is critically examined, and we firmly conclude that Abell 48 is a planetary nebula (PN) around an evolved low-mass star, rather than a Population I ejecta nebula. Importantly, the surrounding nebula has a morphology typical of PNe, and is not enriched in nitrogen, and thus not the `peeled atmosphere' of a massive star. We estimate a distance of 1.6 kpc and a reddening, E(B - V) = 1.90 mag, the latter value clearly showing the nebula lies on the near side of the Galactic bar, and cannot be a massive WN star. The ionized mass (˜0.3 M⊙) and electron density (700 cm-3) are typical of middle-aged PNe. The observed stellar spectrum was compared to a grid of models from the Potsdam Wolf-Rayet (PoWR) grid. The best-fitting temperature is 71 kK, and the atmospheric composition is dominated by helium with an upper limit on the hydrogen abundance of 10 per cent. Our results are in very good agreement with the recent study of Todt et al., who determined a hydrogen fraction of 10 per cent and an unusually large nitrogen fraction of ˜5 per cent. This fraction is higher than any other low-mass H-deficient star, and is not readily explained by current post-AGB models. We give a discussion of the implications of this discovery for the late-stage evolution of intermediate-mass stars. There is now tentative evidence for two distinct helium-dominated post-AGB lineages, separate to the helium- and carbon-dominated surface compositions produced by a late thermal pulse. Further theoretical work is needed to explain these recent discoveries.

  2. The richness dependence of galaxy cluster correlations: results from a redshift survey of rich APM clusters

    NASA Astrophysics Data System (ADS)

    Croft, R. A. C.; Dalton, G. B.; Efstathiou, G.; Sutherland, W. J.; Maddox, S. J.

    1997-10-01

    We analyse the spatial clustering properties of a new catalogue of very rich galaxy clusters with newly measured redshifts selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell richness class≯1 clusters, but selected using an objective algorithm from a catalogue demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function xi_cc(r) for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maximum likelihood estimator to find the best-fitting slope and amplitude of a power-law fit to xi_cc(r), and to estimate the correlation length r_0 [the value of r at which xi_cc(r) is equal to unity]. For clusters with a mean space density of 1.6x10^-6 h^3 Mpc^-3 (equivalent to the space density of Abell richness≯2 clusters), we find r_0=21.3^+11.1_-9.3 h^-1 Mpc (95 per cent confidence limits). This is consistent with the weak richness dependence of xi_cc(r) expected in Gaussian models of structure formation. In particular, the amplitude of xi_cc(r) at all richnesses matches that of xi_cc(r) for clusters selected in N-body simulations of a low-density cold dark matter model.

  3. Core-collapse Supernovae

    SciTech Connect

    Hix, William Raphael; Lentz, E. J.; Baird, Mark L; Chertkow, Merek A; Lee, Ching-Tsai; Blondin, J. M.; Bruenn, S. W.; Messer, Bronson; Mezzacappa, Anthony

    2013-01-01

    Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{51}$ ergs of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

  4. Theoretical models for supernovae

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.

    1981-09-21

    The results of recent numerical simulations of supernova explosions are presented and a variety of topics discussed. Particular emphasis is given to (i) the nucleosynthesis expected from intermediate mass (10sub solar less than or equal to M less than or equal to 100 Msub solar) Type II supernovae and detonating white dwarf models for Type I supernovae, (ii) a realistic estimate of the ..gamma..-line fluxes expected from this nucleosynthesis, (iii) the continued evolution, in one and two dimensions, of intermediate mass stars wherein iron core collapse does not lead to a strong, mass-ejecting shock wave, and (iv) the evolution and explosion of vary massive stars (M greater than or equal to 100 Msub solar of both Population I and III. In one dimension, nuclear burning following a failed core bounce does not appear likely to lead to a supernova explosion although, in two dimensions, a combination of rotation and nuclear burning may do so. Near solar proportions of elements from neon to calcium and very brilliant optical displays may be created by hypernovae, the explosions of stars in the mass range 100 M/sub solar/ to 300 M/sub solar/. Above approx. 300 M/sub solar/ a black hole is created by stellar collapse following carbon ignition. Still more massive stars may be copious producers of /sup 4/He and /sup 14/N prior to their collapse on the pair instability.

  5. QCD and Supernovas

    NASA Astrophysics Data System (ADS)

    Barnes, T.

    2005-12-01

    In this contribution we briefly summarize aspects of the physics of QCD which are relevant to the supernova problem. The topic of greatest importance is the equation of state (EOS) of nuclear and strongly-interacting matter, which is required to describe the physics of the proto-neutron star (PNS) and the neutron star remnant (NSR) formed during a supernova event. Evaluation of the EOS in the regime of relevance for these systems, especially the NSR, requires detailed knowledge of the spectrum and strong interactions of hadrons of the accessible hadronic species, as well as other possible phases of strongly interacting matter, such as the quark-gluon plasma (QGP). The forces between pairs of baryons (both nonstrange and strange) are especially important in determining the EOS at NSR densities. Predictions for these forces are unfortunately rather model dependent where not constrained by data, and there are several suggestions for the QCD mechanism underlying these short-range hadronic interactions. The models most often employed for determining these strong interactions are broadly of two types, 1) meson exchange models (usually assumed in the existing neutron star and supernova literature), and 2) quark-gluon models (mainly encountered in the hadron, nuclear and heavy-ion literature). Here we will discuss the assumptions made in these models, and discuss how they are applied to the determination of hadronic forces that are relevant to the supernova problem.

  6. Supernova Photometric Lightcurve Classification

    NASA Astrophysics Data System (ADS)

    Zaidi, Tayeb; Narayan, Gautham

    2016-01-01

    This is a preliminary report on photometric supernova classification. We first explore the properties of supernova light curves, and attempt to restructure the unevenly sampled and sparse data from assorted datasets to allow for processing and classification. The data was primarily drawn from the Dark Energy Survey (DES) simulated data, created for the Supernova Photometric Classification Challenge. This poster shows a method for producing a non-parametric representation of the light curve data, and applying a Random Forest classifier algorithm to distinguish between supernovae types. We examine the impact of Principal Component Analysis to reduce the dimensionality of the dataset, for future classification work. The classification code will be used in a stage of the ANTARES pipeline, created for use on the Large Synoptic Survey Telescope alert data and other wide-field surveys. The final figure-of-merit for the DES data in the r band was 60% for binary classification (Type I vs II).Zaidi was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program (AST-1262829).

  7. Mass, velocity anisotropy, and pseudo phase-space density profiles of Abell 2142

    NASA Astrophysics Data System (ADS)

    Munari, E.; Biviano, A.; Mamon, G. A.

    2014-06-01

    Aims: We aim to compute the mass and velocity anisotropy profiles of Abell 2142 and, from there, the pseudo phase-space density profile Q(r) and the density slope - velocity anisotropy β - γ relation, and then to compare them with theoretical expectations. Methods: The mass profiles were obtained by using three techniques based on member galaxy kinematics, namely the caustic method, the method of dispersion-kurtosis, and MAMPOSSt. Through the inversion of the Jeans equation, it was possible to compute the velocity anisotropy profiles. Results: The mass profiles, as well as the virial values of mass and radius, computed with the different techniques agree with one another and with the estimates coming from X-ray and weak lensing studies. A combined mass profile is obtained by averaging the lensing, X-ray, and kinematics determinations. The cluster mass profile is well fitted by an NFW profile with c = 4.0 ± 0.5. The population of red and blue galaxies appear to have a different velocity anisotropy configuration, since red galaxies are almost isotropic, while blue galaxies are radially anisotropic, with a weak dependence on radius. The Q(r) profile for the red galaxy population agrees with the theoretical results found in cosmological simulations, suggesting that any bias, relative to the dark matter particles, in velocity dispersion of the red component is independent of radius. The β - γ relation for red galaxies matches the theoretical relation only in the inner region. The deviations might be due to the use of galaxies as tracers of the gravitational potential, unlike the non-collisional tracer used in the theoretical relation.

  8. The dust in the hydrogen-poor ejecta of Abell 30

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Harrington, J. Patrick; Blair, William P.; Bregman, Jesse D.

    1994-01-01

    We present new optical and near-infrared images of the hydrogen-poor planetary nebula Abell 30 and produce detailed models that account for the major observed morphological and IR properties. By imaging the nebula in the K band, we confirm the presence of hot dust in an expanding equatorial ring of H-poor gas. No emission was detected from the H-poor polar knots, suggesting a dust deficiency htere relative to the equatorial ring. The near-IR emission is attributed to small carbonaceous dust grains which are stochastically heated by stellar ultraviolet photons. Using an adaptive version of a matrix method devised by Guhathakurta & Draine (1989) to model stochastic heating, we find that the near-IR spectrum observed by Dinerstein & Lester (1984) requires the presence of dust grains down to approximately 0.0007 microns in radius. This minimum grain radius is in excellent agreement with our calculations of the grain destruction by energetic stellar UV photons: we find that carbon clusters with less than approximately 140 atoms (0.0007 microns in radius) are destroyed by stellar UV photons in approximately 1000 yr, the kinematic age of H-poor ejecta. Modeling of the far-IR dust emission implies that the bulk of the dust mass in A30 must reside at distances several times greater than the distance of the equatorial ring from the central star. This spatial dust distribution is attributed to the interaction of the stellar wind with the inhomogeneous H-poor ejecta. Most of the H-poor gas and dust has been apparently carried outward by the stellar wind, leaving behing dense, H-poor knots with prominent wind-blown tails in the equatorial ring and in the polar knots. This picture is supported by the presence of a stellar wind-blown bubble within the H-rich envelope in our optical images.

  9. Red supergiants as type II supernova progenitors

    NASA Astrophysics Data System (ADS)

    Negueruela, Ignacio; Dorda, Ricardo; González-Fernández, Carlos; Marco, Amparo

    2015-08-01

    Recent searches for supernova IIp progenitors in external galaxies have led to the identification of red objects with magnitudes and colours indicative of red supergiants, in most cases implying quite low luminosities and hence masses well below 10Msol. Stellar models, on the other hand, do not predict explosions from objects below 9 Msol. What does our knowledge of local red supergiants tells us about the expected properties of such objects?We have carried out a comprehensive spectroscopic and photometric study of a sample of hundreds of red supergiants in the Milky Way and both Magellanic Clouds. We have explored correlations between different parameters and the position of stars in the HR diagrams of open clusters. At solar metallicty, there is strong evidence for a phase of very heavy mass loss at the end of the red supergiant phase, but the existence of such a phase is still not confirmed at SMC metallicities. Objects of ~ 7Msol, on the other hand, become very dusty in the SMC, and appear as very luminous Miras.Among Milky Way clusters, we find a surprising lack of objects readily identifiable as the expected 7 to 10 Msol red supergiants or AGB stars. We are carrying out an open cluster survey aimed at filling this region of the HR diagram with reliable data. Finally, we will discuss the implications of all this findings for the expected properties of supernova progenitors, as it looks unlikely that typical red supergiants may explode without undergoing further evolution.

  10. Galaxy Evolution in Rich Clusters

    NASA Astrophysics Data System (ADS)

    Schwarzkopf, U.; Hill, J. M.

    2000-12-01

    We present the first results of a study of the morphological and spectral evolution of galaxies within the dense cores of distant clusters at redshifts between z=0.4 and 1. The morphology, colors, concentration index, and asymmetry parameters of these cluster members are compared by using a combination of deep HST NICMOS and WFPC2 imaging, covering the rest-frame U and J bands. We also discuss the influence of dust obscuration on the derived measurements. Of particular interest is the morphology of galaxies at near-infrared wavelengths in rich clusters which show an excess of blue galaxies (Butcher-Oelmer effect), namely Abell 851 (z=0.4) and CL 1603+43 (z=0.92). We focus our study on optical/near-infrared measurements of galaxy asymmetry and central concentration, derived from a large number (>400) of objects detected within the core of Abell 851. The sensitivity and reliability of these parameters for galaxy classification and physical diagnostic purposes are tested. In conjunction with the use of recent source extraction software we are able to establish a fast, robust, and highly automated procedure of mapping the structural parameters of large galaxy samples. This work is supported by NASA, under contract NAS5-26555.

  11. Galaxy cluster's rotation

    NASA Astrophysics Data System (ADS)

    Manolopoulou, M.; Plionis, M.

    2017-03-01

    We study the possible rotation of cluster galaxies, developing, testing, and applying a novel algorithm which identifies rotation, if such does exist, as well as its rotational centre, its axis orientation, rotational velocity amplitude, and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z ≲ 0.1 with member galaxies selected from the Sloan Digital Sky Survey DR10 spectroscopic data base. After excluding a number of substructured clusters, which could provide erroneous indications of rotation, and taking into account the expected fraction of misidentified coherent substructure velocities for rotation, provided by our Monte Carlo simulation analysis, we find that ∼23 per cent of our clusters are rotating under a set of strict criteria. Loosening the strictness of the criteria, on the expense of introducing spurious rotation indications, we find this fraction increasing to ∼28 per cent. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation within 1.5 h^{-1}_{70} Mpc that the significance of their rotation is related to the dynamically younger phases of cluster formation but after the initial anisotropic accretion and merging has been completed. Finally, finding rotational modes in galaxy clusters could lead to the necessity of correcting the dynamical cluster mass calculations.

  12. Optical Spectroscopy of Hostless Supernovae Candidates

    NASA Astrophysics Data System (ADS)

    Sand, David; Graham, Melissa Lynn; Zaritsky, Dennis; Pritchet, Chris; Hoekstra, Henk; Herbert-Fort, Stephane; Just, Dennis; Sivanandam, Suresh

    2008-08-01

    Observational evidence has indicated that ~30% of the stellar luminosity in galaxy clusters is in a diffuse, extended intracluster component, which originates from stripped and disrupted cluster galaxies. One way to measure the contribution of this diffuse stellar population to both the total cluster stellar luminosity and the metal enrichment of the intracluster medium (ICM) is through the relative rates of intracluster to cluster galaxy supernovae (SNe). We are in the midst of a large program searching for SNe in galaxy clusters at 0.05 < z < 0.15. In order to maximize the scientific return on our SN imaging campaign and other spectroscopic efforts, we seek to continue our ToO program on Gemini North to spectroscopically confirm ALL of our intracluster SNe candidates next semester. We will confirm up to 3 intracluster SNe per semester (~10-15 over the survey lifetime) in our cluster sample, allowing us to constrain the rate of intracluster SNe Ia and their contribution to the metal enrichment of the ICM.

  13. Supernova research with VLBI

    NASA Astrophysics Data System (ADS)

    Bartel, Norbert; Bietenholz, Michael F.

    2016-06-01

    Core-collapse supernovae have been monitored with VLBI from shortly after the explosion to many years thereafter. Radio emission is produced as the ejecta hit the stellar wind left over from the dyingstar. Images show the details of the interaction as the shock front expands into the circumstellar medium. Measurements of the velocity and deceleration of the expansion provide information on both the ejecta and the circumstellar medium. VLBI observations can also search for the stellar remnant of the explosion, a neutron star or a black hole. Combining the transverse expansion rate with the radial expansion rate from optical spectra allows a geometric determination of the distance to the host galaxy. We will present results from recent VLBI observations, focus on their interpretations, and show updated movies of supernovae from soon after their explosion to the present.

  14. Presupernova models and supernovae

    NASA Technical Reports Server (NTRS)

    Sugimoto, D.; Nomoto, K.

    1980-01-01

    The present status of theories of presupernova stellar evolution and the triggering mechanisms of supernova explosions are reviewed. The validity of the single-star approximation for stellar core evolution is considered, and the central density and temperature of the stellar core are discussed. Attention is then given to the results of numerical models of supernova explosions by carbon deflagration of an intermediate mass star, resulting in the total disruption of the star; the photodissociation of iron nuclei in a massive star, resulting in neutron star or black hole formation; and stellar core collapse triggered by electron capture in stars of mass ranging between those of the intermediate mass and massive stars, resulting in neutron star formation despite oxygen deflagration. Helium and carbon combustion and detonation in accreting white dwarfs and the gravitational collapse triggered by electron-pair creation in supermassive stars are also discussed, and problems requiring future investigation are indicated.

  15. Supernova 1987A!

    PubMed

    Woosley, S E; Phillips, M M

    1988-05-06

    Light from the brightest supernova in almost 400 years arrived at Earth on 23 February 1987. Although located 160,000 light years away in a satellite galaxy of our own known as the Large Magellanic Cloud, this supernova's relative proximity compared to all others that have been observed in modern times has allowed observations, which were never possible before, to be made from space, from detectors on the ground and carried by balloons and airplanes, and from neutrino detectors deep underground. What emerges is a greater understanding of one of the most violent events in the universe, the death of a massive star. For the most part, theoretical expectations have been borne out, but some major surprises have made the event all the more fascinating.

  16. Supernova Science Center

    SciTech Connect

    S. E. Woosley

    2008-05-05

    The Supernova Science Center (SNSC) was founded in 2001 to carry out theoretical and computational research leading to a better understanding of supernovae and related transients. The SNSC, a four-institutional collaboration, included scientists from LANL, LLNL, the University of Arizona (UA), and the University of California at Santa Cruz (UCSC). Intitially, the SNSC was funded for three years of operation, but in 2004 an opportunity was provided to submit a renewal proposal for two years. That proposal was funded and subsequently, at UCSC, a one year no-cost extension was granted. The total operational time of the SNSC was thus July 15, 2001 - July 15, 2007. This document summarizes the research and findings of the SNSC and provides a cummulative publication list.

  17. U(1)-invariant membranes: The geometric formulation, Abel, and pendulum differential equations

    SciTech Connect

    Zheltukhin, A. A.; Trzetrzelewski, M.

    2010-06-15

    The geometric approach to study the dynamics of U(1)-invariant membranes is developed. The approach reveals an important role of the Abel nonlinear differential equation of the first type with variable coefficients depending on time and one of the membrane extendedness parameters. The general solution of the Abel equation is constructed. Exact solutions of the whole system of membrane equations in the D=5 Minkowski space-time are found and classified. It is shown that if the radial component of the membrane world vector is only time dependent, then the dynamics is described by the pendulum equation.

  18. Are There Hidden Supernovae?

    NASA Astrophysics Data System (ADS)

    Bregman, Jesse; Harker, David; Dunham, E.; Rank, David; Temi, Pasquale

    1997-02-01

    Ames Research Center and UCSC have been working on the development of a Mid IR Camera for the KAO in order to search for extra galactic supernovae. The development of the camera and its associated data reduction software have been successfully completed. Spectral Imaging of the Orion Bar at 6.2 and 7.8 microns demonstrates the derotation and data reduction software which was developed.

  19. Core bounce supernovae

    SciTech Connect

    Cooperstein, J.

    1987-01-01

    The gravitational collapse mechanism for Type II supernovae is considered, concentrating on the direct implosion - core bounce - hydrodynamic explosion picture. We examine the influence of the stiffness of the dense matter equation of state and discuss how the shock wave is formed. Its chances of success are determined by the equation of state, general relativistic effects, neutrino transport, and the size of presupernova iron core. 12 refs., 1 tab.

  20. Are There Hidden Supernovae?

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse; Harker, David; Dunham, E.; Rank, David; Temi, Pasquale

    1997-01-01

    Ames Research Center and UCSC have been working on the development of a Mid IR Camera for the KAO in order to search for extra galactic supernovae. The development of the camera and its associated data reduction software have been successfully completed. Spectral Imaging of the Orion Bar at 6.2 and 7.8 microns demonstrates the derotation and data reduction software which was developed.

  1. Type IA Supernovae

    NASA Technical Reports Server (NTRS)

    Wheeler, J. Craig

    1992-01-01

    Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.

  2. Supernova Dust Factories

    NASA Astrophysics Data System (ADS)

    Gomez, Haley; Consortium, MESS; LCOGT

    2013-01-01

    The origin of interstellar dust in galaxies is poorly understood, particularly the relative contribution from supernovae. We present infrared and submillimeter photometry and spectroscopy from the Herschel Space Observatory of the Galactic remnants Tycho, Kepler and the Crab Nebula, taken as part of the Mass Loss from Evolved StarS program (MESS). Although we detect small amounts of dust surrounding Tycho and Kepler (the remnants of Type Ia supernovae), we show this is due to swept-up interstellar and circumstellar material respectively. The lack of dust grains in the ejecta suggests that Type Ia remnants do not produce substantial quantities of iron-rich dust grains and has important consequences for the ‘missing’ iron mass observed in ejecta. After carefully subtracting the synchrotron and line emission from the Crab, the remaining far-infrared continuum originates from 0.1-0.2 solar masses of dust. These observations suggest that the Crab Nebula has condensed most of the relevant refractory elements into dust and that these grains appear well set to survive their journey into the interstellar medium. In summary, our Herschel observations show that significantly less dust forms in the ejecta of Type Ia supernovae than in the remnants of core-collapse explosions, placing stringent constraints on the environments in which dust and molecules can form.

  3. Supernovae and Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Mathews, Grant J.

    2014-09-01

    Nucleosynthesis by rapid neutron capture (the r-process) could be an important diagnostic of the explosive deep interiors of supernovae. The early appearance of r-process elements in the Galaxy, along with energetic requirements, strongly argues in favor of a supernova origin for r-process isotopes. However there is a current conundrum as to the relative contributions from various supernovae environments, e.g. MHD jets or neutrino energized winds. There are also possible contributions from failed supernovae (collapsars) leading to a black hole (BH), or the ejection of material during the mergers of neutron stars in binary systems, i.e. NS+NS or NS+BH systems. In this talk we will review the theoretical underpinnings of each possibility in the quest to deduce the relative contribution of each process. In particular, each model for r-process nucleosynthesis invariably leads to systematic discrepancies with the observed solar-system r-process abundances. For example, although the location of the abundance peaks near nuclear mass numbers A = 130 and 195 identify an environment of rapid neutron capture near closed nuclear shells, the abundances of elements just above and below those peaks are often underproduced by more than an order of magnitude in model calculations. Similarly, most recent neutrino-driven wind simulations produce only the lighter r-process elements, while neutron-star mergers may miss the r-process peaks due to fission recycling. In this talk we demonstrate that the underproduction of elements above and below the r-process peaks can be supplemented via fission fragment distributions from the recycling of material synthesized during neutron star mergers, while the abundance peaks themselves are well reproduced in MHD jets in supernovae and collapsars. Moreover, we show that the relative contributions to the solar-system r-process yields from core-collapse supernovae and neutron star mergers required by this proposal are consistent with estimates of the

  4. Supernovae and neutrinos

    SciTech Connect

    John F. Beacom

    2002-09-19

    A long-standing problem in supernova physics is how to measure the total energy and temperature of {nu}{sub {mu}}, {nu}{sub {tau}}, {bar {nu}}{sub {mu}}, and {bar {nu}}{sub {tau}}. While of the highest importance, this is very difficult because these flavors only have neutral-current detector interactions. We propose that neutrino-proton elastic scattering, {nu} + p {yields} {nu} + p, can be used for the detection of supernova neutrinos in scintillator detectors. It should be emphasized immediately that the dominant signal is on free protons. Though the proton recoil kinetic energy spectrum is soft, with T{sub p} {approx_equal} 2E{sub {nu}}{sup 2}/M{sub p}, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from {bar {nu}}{sub e} + p {yields} e{sup +} + n. In addition, the measured proton spectrum is related to the incident neutrino spectrum. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.

  5. Aluminum could be transported via phloem in Camellia oleifera Abel.

    PubMed

    Zeng, Qi Long; Chen, Rong Fu; Zhao, Xue Qiang; Shen, Ren Fang; Noguchi, Akira; Shinmachi, Fumie; Hasegawa, Isao

    2013-01-01

    Aluminum (Al) accumulation and long-distance transport in oil tea (Camellia oleifera Abel.), known to be an Al accumulator, was investigated. The average Al concentration in the embryo of oil tea seeds was 389 mg Al kg(-1) dry weight, which was higher than seeds of other Al accumulators. By partially suppressing leaf transpiration in the field, Al accumulation in leaves was depressed, which clarified the importance of xylem transport to Al accumulation in leaves. However, the effects of xylem transport alone could not sufficiently explain the high Al accumulation in the seasons when the leaf transpiration is weak, which hints the necessity of phloem transport working. Aluminum content in phloem exudates of barks provides another evidence of phloem transport. Images from scanning electron microscopy and energy-dispersive analysis also showed that Al was present in the phloem of oil tea petioles. Aluminum in oil tea could also be redistributed: higher concentrations of Al were found in leaves when Al was supplied to a different leaf of the same plant. In addition, Al was present in newly emerging roots of oil tea seedlings in which all original roots were excised prior to treatment, and a positive correlation existed between Al content in the newly formed roots and that in the leaves. The results using the empty seed coat technique showed that Al unloading via the phloem occurred during seed development. In conclusion, the results demonstrated that Al could be redistributed between leaves, from seeds to leaves, leaves to roots and leaves to seeds, which indicates that Al can be transported via the phloem in oil tea.

  6. Interacting supernovae and supernova impostors: Evidence of incoming supernova explosions?

    SciTech Connect

    Tartaglia, L.

    2015-02-24

    Violent eruptions, and consequently major mass loss, are a common feature of the so–called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8{sub ⊙}) exploding in a dense H–rich circumstellar medium (CSM), produced by progenitor’s mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ∼3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage.

  7. Interacting supernovae and supernova impostors: Evidence of incoming supernova explosions?

    NASA Astrophysics Data System (ADS)

    Tartaglia, L.

    2015-02-01

    Violent eruptions, and consequently major mass loss, are a common feature of the so-called Luminous Blue Variable (LBV) stars. During major eruptive episodes LBVs mimic the behavior of real type IIn supernovae (SNe), showing comparable radiated energy and similar spectroscopic properties. For this reason these events are frequently labelled as SN impostors. Type IIn SN spectra are characterized by the presence of prominent narrow Balmer lines in emission. In most cases, SNe IIn arise from massive stars (M>8⊙) exploding in a dense H-rich circumstellar medium (CSM), produced by progenitor's mass loss prior to the SN explosion. Although the mechanisms triggering these eruptions are still unknown, recently we had direct proofs of the connection between very massive stars, their eruptions and ejecta-CSM interacting SNe. SNe 2006jc, 2010mc, 2011ht and the controversial SN 2009ip are famous cases in which we observed the explosion of the star months to years after major outbursts. In this context, the case of a recent transient event, LSQ13zm, is extremely interesting since we observed an outburst just ˜3 weeks before the terminal SN explosion. All of this may suggest that SN impostors occasionally herald true SN explosions. Nonetheless, there are several cases where major eruptions are followed by a quiescent phase in the LBV life. The impostor SN 2007sv is one of these cases, since it showed a single outburst event. Its photometric (a relatively faint absolute magnitude at the maximum) and spectroscopic properties (low velocity and temperature of the ejecta, and the absence of the typical elements produced in the explosive nucleosynthesis) strongly suggest that SN 2007sv was the giant eruption of an LBV, which has then returned in a quiescent stage.

  8. Generalization of Abel's mechanical problem: The extended isochronicity condition and the superposition principle

    SciTech Connect

    Kinugawa, Tohru

    2014-02-15

    This paper presents a simple but nontrivial generalization of Abel's mechanical problem, based on the extended isochronicity condition and the superposition principle. There are two primary aims. The first one is to reveal the linear relation between the transit-time T and the travel-length X hidden behind the isochronicity problem that is usually discussed in terms of the nonlinear equation of motion (d{sup 2}X)/(dt{sup 2}) +(dU)/(dX) =0 with U(X) being an unknown potential. Second, the isochronicity condition is extended for the possible Abel-transform approach to designing the isochronous trajectories of charged particles in spectrometers and/or accelerators for time-resolving experiments. Our approach is based on the integral formula for the oscillatory motion by Landau and Lifshitz [Mechanics (Pergamon, Oxford, 1976), pp. 27–29]. The same formula is used to treat the non-periodic motion that is driven by U(X). Specifically, this unknown potential is determined by the (linear) Abel transform X(U) ∝ A[T(E)], where X(U) is the inverse function of U(X), A=(1/√(π))∫{sub 0}{sup E}dU/√(E−U) is the so-called Abel operator, and T(E) is the prescribed transit-time for a particle with energy E to spend in the region of interest. Based on this Abel-transform approach, we have introduced the extended isochronicity condition: typically, τ = T{sub A}(E) + T{sub N}(E) where τ is a constant period, T{sub A}(E) is the transit-time in the Abel type [A-type] region spanning X > 0 and T{sub N}(E) is that in the Non-Abel type [N-type] region covering X < 0. As for the A-type region in X > 0, the unknown inverse function X{sub A}(U) is determined from T{sub A}(E) via the Abel-transform relation X{sub A}(U) ∝ A[T{sub A}(E)]. In contrast, the N-type region in X < 0 does not ensure this linear relation: the region is covered with a predetermined potential U{sub N}(X) of some arbitrary choice, not necessarily obeying the Abel-transform relation. In discussing

  9. Supernova Discoveries from the Nearby Supernova Factory (SNfactory)

    DOE Data Explorer

    SNfactory International Collaboration,

    The Nearby Supernova Factory is an experiment designed to collect data on more Type Ia supernovae than have ever been studied in a single project before, and in so doing, to answer some fundamental questions about the nature of the universe. Type Ia supernovae are extraordinarily bright, remarkably uniform objects which make excellent "standard candles" for measuring the expansion rate of the universe. However, such stellar explosions are very rare, occurring only a couple of times per millenium in a typical galaxy, and remaining bright enough to detect only for a few weeks. Previous studies of Type Ia supernovae led to the discovery of the mysterious "dark energy" that is causing the universe to expand at an accelerating rate. To reduce the statistical uncertainties in previous experimental data, extensive spectral and photometric monitoring of more Type Ia supernovae is required. The SNfactory collaboration has built an automated system consisting of specialized software and custom-built hardware that systematically searches the sky for new supernovae, screens potential candidates, then performs multiple spectral and photometric observations on each supernova. These observations are stored in a database to be made available to supernova researchers world-wide for further study and analysis [copied from http://snfactory.lbl.gov/snf/snf-about.html]. Users must register and agree to the open access honor system. Finding charts are in FITS format and may not be accessible through normal browser settings.

  10. The ASTRODEEP Frontier Fields catalogues. I. Multiwavelength photometry of Abell-2744 and MACS-J0416

    NASA Astrophysics Data System (ADS)

    Merlin, E.; Amorín, R.; Castellano, M.; Fontana, A.; Buitrago, F.; Dunlop, J. S.; Elbaz, D.; Boucaud, A.; Bourne, N.; Boutsia, K.; Brammer, G.; Bruce, V. A.; Capak, P.; Cappelluti, N.; Ciesla, L.; Comastri, A.; Cullen, F.; Derriere, S.; Faber, S. M.; Ferguson, H. C.; Giallongo, E.; Grazian, A.; Lotz, J.; Michałowski, M. J.; Paris, D.; Pentericci, L.; Pilo, S.; Santini, P.; Schreiber, C.; Shu, X.; Wang, T.

    2016-05-01

    Context. The Frontier Fields survey is a pioneering observational program aimed at collecting photometric data, both from space (Hubble Space Telescope and Spitzer Space Telescope) and from ground-based facilities (VLT Hawk-I), for six deep fields pointing at clusters of galaxies and six nearby deep parallel fields, in a wide range of passbands. The analysis of these data is a natural outcome of the Astrodeep project, an EU collaboration aimed at developing methods and tools for extragalactic photometry and creating valuable public photometric catalogues. Aims: We produce multiwavelength photometric catalogues (from B to 4.5 μm) for the first two of the Frontier Fields, Abell-2744 and MACS-J0416 (plus their parallel fields). Methods: To detect faint sources even in the central regions of the clusters, we develop a robust and repeatable procedure that uses the public codes Galapagos and Galfit to model and remove most of the light contribution from both the brightest cluster members, and the intra-cluster light. We perform the detection on the processed HST H160 image to obtain a pure H-selected sample, which is the primary catalogue that we publish. We also add a sample of sources which are undetected in the H160 image but appear on a stacked infrared image. Photometry on the other HST bands is obtained using SExtractor, again on processed images after the procedure for foreground light removal. Photometry on the Hawk-I and IRAC bands is obtained using our PSF-matching deconfusion code t-phot. A similar procedure, but without the need for the foreground light removal, is adopted for the Parallel fields. Results: The procedure of foreground light subtraction allows for the detection and the photometric measurements of ~2500 sources per field. We deliver and release complete photometric H-detected catalogues, with the addition of the complementary sample of infrared-detected sources. All objects have multiwavelength coverage including B to H HST bands, plus K

  11. The cosmic distance scale - Methods for determining the distance to supernovae

    NASA Technical Reports Server (NTRS)

    Arnett, W. D.

    1982-01-01

    It is established by an analysis of alternative methods for the determination of absolute distances to supernovae that there exists a kinematic method, superior to that of Baade (1926), which is illustrated for the case of the Type I supernova 1975a in NGC 2207. In addition, a dynamical method is developed which employs the recently-discovered analytic solutions for Type I supernovae. The requirement that the paradigm invoked in the present study be able to reproduce both fast and slow light curves has implied a dispersion in intrinsic brightness, whose size is approximately that observed in the Virgo and Coma clusters.

  12. Texas Supernova Search: A Wide Field Search for Nearby SNe

    NASA Astrophysics Data System (ADS)

    Quimby, R. M.; Castro, F.; Gerardy, C. L.; Hoeflich, P.; Kannappan, S. J.; Mondol, P.; Sellers, M.; Wheeler, J. C.

    2005-12-01

    ROTSE-IIIb is one four robotic telescopes built by the University of Michigan to observe the prompt optical afterglows associated with gamma-ray bursts. At just 0.45m in diameter, it is the smallest research telescope at McDonald, but its 1.85 x 1.85 deg field of view and autonomous operation make it an excellent survey instrument for rare transient phenomena. We have been using ROTSE-IIIb for the past year to search for supernovae in nearby galaxy clusters such as the Virgo, Coma, and Ursa Major clusters. ROTSE-IIIb's wide field of view allows us to search the thousands of galaxies in these clusters, which cover hundreds of square degrees on the sky, in just a few tens of exposures. We can therefore observe all of these fields in a single night, and repeat the search every night. When we identify a new supernova candidate, we invoke our target of opportunity time on the neighboring 9.2m Hobby-Eberly Telescope (HET) the following night to obtain a spectrum. Because of the rolling search and the quick spectral turn-around possible with the HET, we are able to capture spectra of the earliest phases of the explosion. By combining this information with spectra taken at later epochs, we can construct a complete description of the explosion. Through this work we aim to better understand the physical conditions of supernova explosions, identify any systematic effects that may affect how Type Ia supernovae are calibrated as standard candles and used to probe cosmology, and also to better calibrate Type II supernovae as standard candles.

  13. Collective neutrino oscillations in supernovae

    SciTech Connect

    Duan, Huaiyu

    2014-06-24

    In a dense neutrino medium neutrinos can experience collective flavor transformation through the neutrino-neutrino forward scattering. In this talk we present some basic features of collective neutrino flavor transformation in the context in core-collapse supernovae. We also give some qualitative arguments for why and when this interesting phenomenon may occur and how it may affect supernova nucleosynthesis.

  14. Gravitational Lensing of Supernova Neutrinos

    SciTech Connect

    Mena, Olga; Mocioiu, Irina; Quigg, Chris; /Fermilab

    2006-10-01

    The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse.

  15. THE DYNAMICAL STATE OF BRIGHTEST CLUSTER GALAXIES AND THE FORMATION OF CLUSTERS

    SciTech Connect

    Coziol, R.; Andernach, H.; Caretta, C. A.; Alamo-MartInez, K. A.; Tago, E. E-mail: heinz@astro.ugto.mx E-mail: k.alamo@astrosmo.unam.mx

    2009-06-15

    A large sample of Abell clusters of galaxies, selected for the likely presence of a dominant galaxy, is used to study the dynamical properties of the brightest cluster members (BCMs). From visual inspection of Digitized Sky Survey images combined with redshift information we identify 1426 candidate BCMs located in 1221 different redshift components associated with 1169 different Abell clusters. This is the largest sample published so far of such galaxies. From our own morphological classification we find that {approx}92% of the BCMs in our sample are early-type galaxies and 48% are of cD type. We confirm what was previously observed based on much smaller samples, namely, that a large fraction of BCMs have significant peculiar velocities. From a subsample of 452 clusters having at least 10 measured radial velocities, we estimate a median BCM peculiar velocity of 32% of their host clusters' radial velocity dispersion. This suggests that most BCMs are not at rest in the potential well of their clusters. This phenomenon is common to galaxy clusters in our sample, and not a special trait of clusters hosting cD galaxies. We show that the peculiar velocity of the BCM is independent of cluster richness and only slightly dependent on the Bautz-Morgan type. We also find a weak trend for the peculiar velocity to rise with the cluster velocity dispersion. The strongest dependence is with the morphological type of the BCM: cD galaxies tend to have lower relative peculiar velocities than elliptical galaxies. This result points to a connection between the formation of the BCMs and that of their clusters. Our data are qualitatively consistent with the merging-groups scenario, where BCMs in clusters formed first in smaller subsystems comparable to compact groups of galaxies. In this scenario, clusters would have formed recently from the mergers of many such groups and would still be in a dynamically unrelaxed state.

  16. Globular Cluster Systems in Brightest Cluster Galaxies. III: Beyond Bimodality

    NASA Astrophysics Data System (ADS)

    Harris, William E.; Ciccone, Stephanie M.; Eadie, Gwendolyn M.; Gnedin, Oleg Y.; Geisler, Douglas; Rothberg, Barry; Bailin, Jeremy

    2017-01-01

    We present new deep photometry of the rich globular cluster (GC) systems around the Brightest Cluster Galaxies UGC 9799 (Abell 2052) and UGC 10143 (Abell 2147), obtained with the Hubble Space Telescope (HST) ACS and WFC3 cameras. For comparison, we also present new reductions of similar HST/ACS data for the Coma supergiants NGC 4874 and 4889. All four of these galaxies have huge cluster populations (to the radial limits of our data, comprising from 12,000 to 23,000 clusters per galaxy). The metallicity distribution functions (MDFs) of the GCs can still be matched by a bimodal-Gaussian form where the metal-rich and metal-poor modes are separated by ≃ 0.8 dex, but the internal dispersions of each mode are so large that the total MDF becomes very broad and nearly continuous from [Fe/H] ≃ ‑2.4 to solar. There are, however, significant differences between galaxies in the relative numbers of metal-rich clusters, suggesting that they underwent significantly different histories of mergers with massive gas-rich halos. Last, the proportion of metal-poor GCs rises especially rapidly outside projected radii R≳ 4 {R}{eff}, suggesting the importance of accreted dwarf satellites in the outer halo. Comprehensive models for the formation of GCs as part of the hierarchical formation of their parent galaxies will be needed to trace the systematic change in structure of the MDF with galaxy mass, from the distinctly bimodal form in smaller galaxies up to the broad continuum that we see in the very largest systems.

  17. Nuclear astrophysics of supernovae

    SciTech Connect

    Cooperstein, J.

    1988-01-01

    In this paper, I'll give a general introduction to Supernova Theory, beginning with the presupernova evolution and ending with the later stages of the explosion. This will be distilled from a colloquium type of talk. It is necessary to have the whole supernova picture in one's mind's eye when diving into some of its nooks and crannies, as it is quite a mess of contradictory ingredients. We will have some discussion of supernova 1987a, but will keep our discussion more general. Second, we'll look at the infall and bounce of the star, seeing why it goes unstable, what dynamics it follows as it collapses, and how and why it bounces back. From there, we will go on to look at the equation of state (EOS) in more detail. We'll consider the cases T = 0 and T > 0. We'll focus on /rho/ < /rho//sub 0/, and then /rho/ > /rho//sub 0/ and the EOS of neutron stars, and whether or not they contain cores of strange matter. There are many things we could discuss here and not enough time. If I had more lectures, the remaining time would focus on two more questions of special interest to nuclear physicists: the electron capture reactions and neutrino transport. If time permitted, we'd have some discussion of the nucleosynthetic reactions in the explosion's debris as well. However, we cannot cover such material adequately, and I have chosen these topics because they are analytically tractable, pedagogically useful, and rather important. 23 refs., 14 figs., 3 tabs.

  18. Cosmological and supernova neutrinos

    SciTech Connect

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Suzuki, T.

    2014-06-24

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  19. Cosmological and supernova neutrinos

    NASA Astrophysics Data System (ADS)

    Kajino, T.; Aoki, W.; Balantekin, A. B.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Kusakabe, M.; Mathews, G. J.; Nakamura, K.; Pehlivan, Y.; Shibagaki, S.; Suzuki, T.

    2014-06-01

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial 7Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and 7Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like 7Li, 11B, 92Nb, 138La and 180Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on θ13 with predicted and observed supernova-produced abundance ratio 11B/7Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  20. GALAXY OUTFLOWS WITHOUT SUPERNOVAE

    SciTech Connect

    Sur, Sharanya; Scannapieco, Evan; Ostriker, Eve C. E-mail: sharanya.sur@asu.edu

    2016-02-10

    High surface density, rapidly star-forming galaxies are observed to have ≈50–100 km s{sup −1} line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds ≈35 km s{sup −1}, as occurs in the dense disks that have star-formation rate (SFR) densities above ≈0.1 M{sub ⊙} yr{sup −1} kpc{sup −2}. These outflows are triggered by a thermal runaway, arising from the inefficient cooling of hot material coupled with successive heating from turbulent driving. Thus, even in the absence of stellar feedback, a critical value of the SFR density for outflow generation can arise due to a turbulent heating instability. This suggests that in strongly self-gravitating disks, outflows may be enhanced by, but need not caused by, energy input from supernovae.

  1. Radio Emission from Supernovae

    SciTech Connect

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; Van Dyk, Schuyler D.; Stockdale, Christopher J.; Kelley, Matthew T.

    2009-05-03

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

  2. Supernova 2002hi

    NASA Astrophysics Data System (ADS)

    Pooley, D.; Lewin, W. H. G.

    2003-01-01

    D. Pooley and W. H. G. Lewin, Massachusetts Institute of Technology, on behalf of a larger collaboration, report the detection of X-ray emission at the position of the type-IIn supernova (SN) 2002hi (IAUC 8006) with the Chandra X-ray observatory: An ACIS-S3 observation of 10 ks was made on Dec. 10.73. In the 0.5-10 keV range, we searched a 2x2 pixel region (approx. 1" by 1") around the reported position of the SN and detected 2 counts.

  3. CRTS Supernova Candidate

    NASA Astrophysics Data System (ADS)

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Williams, R.; Mahabal, A.; Beshore, E. C.; Larson, S. M.; Hill, R.; Catelan, M.; Christensen, E.

    2008-09-01

    We have detected a likely supernova in CSS images from 24 Sep 2008 UT. The object has the following parameters:

    CSS080924:044524+182425 2008-09-24 UT 11:17:06 RA 04:45:24.00 Dec 18:24:25.1 Mag 17.5 Type SN
    The object is near the edge of galaxy LCSB L0250N (z=0.0155).

  4. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    SciTech Connect

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  5. A counter-image to the gravitational arc in Abell 1201:Evidence for IMF variations, or a 1010 M⊙ black hole?

    NASA Astrophysics Data System (ADS)

    Smith, Russell J.; Lucey, John R.; Edge, Alastair C.

    2017-01-01

    Abell 1201 is a massive galaxy cluster at z=0.169 with a brightest cluster galaxy (BCG) that acts as a gravitational lens to a background source at z=0.451. The lensing configuration is unusual, with a single bright arc formed at small radius (˜2 arcsec), where stars and dark matter are both expected to contribute substantially to the total lensing mass. Here, we present deep spectroscopic observations of the Abell 1201 BCG with MUSE, which reveal emission lines from a faint counter-image, opposite to the main arc, at a radius of 0.6 arcsec. We explore models in which the lensing mass is described by a combination of stellar mass and a standard dark-matter halo. The counter-image is not predicted in such models, unless the dark-matter component is negligible, which would imply an extremely heavy stellar initial mass function (IMF) in this galaxy. We consider two modifications to the model which can produce the observed configuration without resorting to extreme IMFs. Imposing a radial gradient in the stellar mass-to-light ratio, Υ, can generate a counter-image close to the observed position if Υ increases by ≳60 per cent within the inner ˜1 arcsec (e.g. variation from a Milky-Way-like to a Salpeter-like IMF). Alternatively, the counter-image can be produced by introducing a central super-massive black hole. The required mass is MBH = (1.3±0.6)× 1010 M⊙, which is comparable to the largest black holes known to date, several of which are also hosted by BCGs. We comment on future observations which promise to distinguish between these alternatives.

  6. Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae

    SciTech Connect

    Albert, J.; Aldering, G.; Allam, S.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Aumeunier, M.; Bailey, S.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstom, L.; Bernstein, G.; Bester, M.; Besuner, B.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; /Caltech /LBL, Berkeley /Fermilab /SLAC /Stockholm U. /Paris, IN2P3 /Marseille, CPPM /Marseille, Lab. Astrophys. /Yale U. /Pennsylvania U. /UC, Berkeley /Michigan U. /Baltimore, Space Telescope Sci. /Indiana U. /Caltech, JPL /Australian Natl. U., Canberra /American Astron. Society /Chicago U. /Cambridge U. /Saclay /Lyon, IPN

    2005-08-08

    The Supernova Acceleration Probe (SNAP) will use Type Ia supernovae (SNe Ia) as distance indicators to measure the effect of dark energy on the expansion history of the Universe. (SNAP's weak-lensing program is described in a separate White Paper.) The experiment exploits supernova distance measurements up to their fundamental systematic limit; strict requirements on the monitoring of each supernova's properties leads to the need for a space-based mission. Results from pre-SNAP experiments, which characterize fundamental SN Ia properties, will be used to optimize the SNAP observing strategy to yield data, which minimize both systematic and statistical uncertainties. With early R&D funding, we have achieved technological readiness and the collaboration is poised to begin construction. Pre-JDEM AO R&D support will further reduce technical and cost risk. Specific details on the SNAP mission can be found in Aldering et al. (2004, 2005). The primary goal of the SNAP supernova program is to provide a dataset which gives tight constraints on parameters which characterize the dark-energy, e.g. w{sub 0} and w{sub a} where w(a) = w{sub 0} + w{sub a}(1-a). SNAP data can also be used to directly test and discriminate among specific dark energy models. We will do so by building the Hubble diagram of high-redshift supernovae, the same methodology used in the original discovery of the acceleration of the expansion of the Universe that established the existence of dark energy (Perlmutter et al. 1998; Garnavich et al. 1998; Riess et al. 1998; Perlmutter et al. 1999). The SNAP SN Ia program focuses on minimizing the systematic floor of the supernova method through the use of characterized supernovae that can be sorted into subsets based on subtle signatures of heterogeneity. Subsets may be defined based on host-galaxy morphology, spectral-feature strength and velocity, early-time behavior, inter alia. Independent cosmological analysis of each subset of ''like'' supernovae can be

  7. Discovery of an Obscured Supernova in Arp 299

    NASA Technical Reports Server (NTRS)

    Neff, Susan; Ulvstad, James; Teng, Stacy

    2003-01-01

    The galaxy merger Arp 299, at a distance of 40 Mpc, is one of the most extensively studied interacting starburst galaxies known. It has been the site of 4 known supernovae (SNe) since 1990. Arp 299 contains a number of strong radio and infrared condensations, with the strongest starburst occurring in 'Source A,' in the nuclear region of the eastern galaxy. Source A has an inferred supernova rate of 0.5-0.7/yr, and its star formation peaked 6-8 Myr ago. Our recent observations identify a new radio-loud SN in Source A, which occurred sometime between April 2002 and February 2003. We imaged Arp 299 at milliarcsecond resolution at two epochs, in April 2002 and February 2003, using the Very Long Baseline Array and (at the first epoch) the Green Bank Telescope. In 2002, four compact radio sources were found in Source A at 2.3 GHz, with flux densities ranging from 0.3 to 1.7 mJy. In 2003, 8.4 GEz images revealed a new 3 mJy source, as well as the four objects detected a year earlier. The new radio SN is more than 1000 times more powerful than the galactic supernova remnant Cassiopeia A and is located located only 12 milliarcseconds (2.5 pc projected) from the strongest source seen in 2002. Milliarcsecond radio imaging is the only technique that could have detected this supernova, since it is embedded within an 80 mJy VLA source and buried in gas and dust (Av 15-25 mag). We suggest that both the new supernova and its nearest neighbor are occurring within a super star cluster, perhaps a newly formed globular cluster akin to those seen in a number of nearby galaxies and particularly galaxy mergers. If so, we are observing this cluster just as its massive stars have begun to explode into a very dense surrounding medium. The likelihood that most supernovae in such a medium will be radio-loud implies that future VLBI imaging over a number of years could lead to a direct measurement of the supernova rate in the Source A starburst, placing powerful constraints on models of

  8. Automated Supernova Discovery (Abstract)

    NASA Astrophysics Data System (ADS)

    Post, R. S.

    2015-12-01

    (Abstract only) We are developing a system of robotic telescopes for automatic recognition of Supernovas as well as other transient events in collaboration with the Puckett Supernova Search Team. At the SAS2014 meeting, the discovery program, SNARE, was first described. Since then, it has been continuously improved to handle searches under a wide variety of atmospheric conditions. Currently, two telescopes are used to build a reference library while searching for PSN with a partial library. Since data is taken every night without clouds, we must deal with varying atmospheric and high background illumination from the moon. Software is configured to identify a PSN, reshoot for verification with options to change the run plan to acquire photometric or spectrographic data. The telescopes are 24-inch CDK24, with Alta U230 cameras, one in CA and one in NM. Images and run plans are sent between sites so the CA telescope can search while photometry is done in NM. Our goal is to find bright PSNs with magnitude 17.5 or less which is the limit of our planned spectroscopy. We present results from our first automated PSN discoveries and plans for PSN data acquisition.

  9. X-ray luminosity functions of clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Cavaliere, A.; Burg, R.; Giacconi, R.

    1991-01-01

    Clusters of galaxies must have a considerable intrinsic spread in their X-ray luminosities at given mass if they are formed bottom-up by direct gravitational instability. The distributions of luminosities at given mass take on the general form of a flat power law with a sharp upper cutoff, consistent with the recently obtained luminosity functions for Abell clusters of given richness classes. The quantitative features depend on the specific hierarchical cosmogony, with models including mass accretion after first collapse providing the best agreement. The same clustering mechanism, after integrating over mass, yields a steep overall luminosity function consistent with existing measurements.

  10. Clusters as cornerstones of large-scale structure.

    NASA Astrophysics Data System (ADS)

    Gottlöber, S.; Retzlaff, J.; Turchaninov, V.

    1997-04-01

    Galaxy clusters are one of the best tracers of large-scale structure in the Universe on scales well above 100 Mpc. The authors investigate here the clustering properties of a redshift sample of Abell/ACO clusters and compare the observational sample with mock samples constructed from N-body simulations on the basis of four different cosmological models. The authors discuss the power spectrum, the Minkowski functionals and the void statistics of these samples and conclude, that the SCDM and TCDM models are ruled out whereas the ACDM and BSI models are in agreement with the observational data.

  11. The LCOGT Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis; Valenti, Stefano; Lcogt Supernova Key Project

    2015-01-01

    I present first results from the Las Cumbres Observatory Global Telescope Network (LCOGT) Supernova Key Project. LCOGT is a network of 11 robotic one and two meter telescopes spaced around the globe with imaging and spectroscopic capabilities. The supernova key project is a 3 year program to obtain lightcurves and spectra of at least 450 supernovae. About half are expected to be core-collapse supernovae, and half thermonuclear. We will start light curves and spectroscopy within hours of discovery, and focus on those SNe caught soon after explosion. The goals are fivefold: (1) observe supernovae soon after explosion to search for signs of their progenitors, (2) obtain a large homogeneous sample of supernovae for next generation cosmological studies, (3) obtain a large sample of supernovae for statistical studies comparing groups that are split into different populations, (4) obtain some of the first large samples of the recently discovered classes of rare and exotic explosions, (5) obtain the optical light curves and spectroscopy in support of studies at other wavelengths and using other facilities including UV observations, IR imaging and spectroscopy, host galaxy studies, high resolution spectroscopy, and late-time spectroscopy with large telescopes.

  12. Hard X-Ray Properties of the Merging Cluster Abell 3667 as Observed with Suzaku

    DTIC Science & Technology

    2008-08-01

    highest sensitivity at around 100 keV using the novel narrow-field-of-view Compton camera concept. It will open a new window to the widely distributed non...GeV energy are under- going cooling due to synchrotron and inverse Compton (IC) emissions. In every case, the radio halos/relics are found in...center and the north-west relic, with the highest sensitivity in the 10–40 keV band. In addition, the X-ray CCD cameras (XISs: Koyama et al. 2007

  13. The art in Abel Salazar's life (1889-1946)--a Portuguese Renaissance spirit of the twentieth century.

    PubMed

    Nabais, João-Maria

    2008-12-01

    Abel Salazar was a true renaissance spirit, scientist, doctor, humanist, artist and writer. His paintings combined realism with a very strong social sense. This article looks at his art and the influence that he had through it on his contemporaries.

  14. Improved Abel transform inversion: First application to COSMIC/FORMOSAT-3

    NASA Astrophysics Data System (ADS)

    Aragon-Angel, A.; Hernandez-Pajares, M.; Juan, J.; Sanz, J.

    2007-05-01

    In this paper the first results of Ionospheric Tomographic inversion are presented, using the Improved Abel Transform on the COSMIC/FORMOSAT-3 constellation of 6 LEO satellites, carrying on-board GPS receivers.[- 4mm] The Abel transform inversion is a wide used technique which in the ionospheric context makes it possible to retrieve electron densities as a function of height based of STEC (Slant Total Electron Content) data gathered from GPS receivers on board of LEO (Low Earth Orbit) satellites. Within this precise use, the classical approach of the Abel inversion is based on the assumption of spherical symmetry of the electron density in the vicinity of an occultation, meaning that the electron content varies in height but not horizontally. In particular, one implication of this assumption is that the VTEC (Vertical Total Electron Content) is a constant value for the occultation region. This assumption may not always be valid since horizontal ionospheric gradients (a very frequent feature in some ionosphere problematic areas such as the Equatorial region) could significantly affect the electron profiles. [- 4mm] In order to overcome this limitation/problem of the classical Abel inversion, a studied improvement of this technique can be obtained by assuming separability in the electron density (see Hernández-Pajares et al. 2000). This means that the electron density can be expressed by the multiplication of VTEC data and a shape function which assumes all the height dependency in it while the VTEC data keeps the horizontal dependency. Actually, it is more realistic to assume that this shape fuction depends only on the height and to use VTEC information to take into account the horizontal variation rather than considering spherical symmetry in the electron density function as it has been carried out in the classical approach of the Abel inversion.[-4mm] Since the above mentioned improved Abel inversion technique has already been tested and proven to be a useful

  15. Tidally-Induced Thermonuclear Supernovae

    SciTech Connect

    Rosswog, S.; Ramirez-Ruiz, E.; Hix, William Raphael

    2009-01-01

    We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and nuclear evolution from the initial parabolic orbit over the disruption to the build-up of an accretion disk around the black hole. For strong enough encounters (pericentre distances smaller than about 1/3 of the tidal radius) the tidal compression is reversed by a shock and finally results in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar limit, we find exploding examples throughout the whole white dwarf mass range. There is, however, a restriction on the masses of the involved black holes: black holes more massive than 2x105M{circle_dot} swallow a typical 0.6M{circle_dot} white dwarf before their tidal forces can overwhelm the star's selfgravity. Therefore, this mechanism is characteristic for black holes of moderate masses. The material that remains bound to the black hole settles into an accretion disk and produces an Xray flare close to the Eddington limit of L{sub Edd} {approx} 10{sup 41}erg/s (Mbh/1000M{circle_dot}), typically lasting for a few months. The combination of a peculiar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate-mass black holes. The next generation of wide field space-based instruments should be able to detect such events.

  16. Supernova 1987A: The Supernova of a Lifetime

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert

    2017-01-01

    Supernova 1987A, the brightest supernova since Kepler's in 1604, was detected 30 years ago at a distance of 160 000 light years in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. Visible with the naked eye and detected with the full range of technology constructed since Kepler's time, SN 1987A has continued to be a rich source of empirical information to help understand supernova explosions and their evolution into supernova remnants. While the light output has faded by a factor of 10 000 000 over those 30 years, instrumentation, like the Hubble Space Telescope, the Chandra X-ray Observatory, and the Atacama Large Millimeter Array has continued to improve so that this supernova continues to be visible in X-rays, ultraviolet light, visible light, infrared light and in radio emission. In this review, I will sketch what has been learned from these observations about the pre-supernova star and its final stages of evolution, the explosion physics, the energy sources for emission, and the shock physics as the expanding debris encounters the circumstellar ring that was created about 20 000 years before the explosion. Today, SN 1987A is making the transition to a supernova remnant- the energetics are no longer dominated by the radioactive elements produced in the explosion, but by the interaction of the expanding debris with the surrounding gas. While we are confident that the supernova explosion had its origin in gravitational collapse, careful searches for a compact object at the center of the remnant place upper limits of a few solar luminosities on that relic. Support for HST GO programs 13401 and 13405 was provided by NASA through grants from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  17. Direct measurement of lensing amplification in Abell S1063 using a strongly lensed high redshift HII galaxy

    NASA Astrophysics Data System (ADS)

    Terlevich, Roberto; Melnick, Jorge; Terlevich, Elena; Chávez, Ricardo; Telles, Eduardo; Bresolin, Fabio; Plionis, Manolis; Basilakos, Spyros; Fernández Arenas, David; González Morán, Ana Luisa; Díaz, Ángeles I.; Aretxaga, Itziar

    2016-08-01

    ID11 is an actively star-forming, extremely compact galaxy and Lyα emitter at z = 3.117 that is gravitationally magnified by a factor of ~17 by the cluster of galaxies Hubble Frontier Fields AS1063. The observed properties of this galaxy resemble those of low luminosity HII galaxies or giant HII regions such as 30 Doradus in the Large Magellanic Cloud. Using the tight correlation correlation between the Balmer-line luminosities and the width of the emission lines (typically L(Hβ) - σ(Hβ)), which are valid for HII galaxies and giant HII regions to estimate their total luminosity, we are able to measure the lensing amplification of ID11. We obtain an amplification of 23 ± 11 that is similar within errors to the value of ~17 estimated or predicted by the best lensing models of the massive cluster Abell S1063. We also compiled, from the literature, luminosities and velocity dispersions for a set of lensed compact star-forming regions. There is more scatter in the L-σ correlation for these lensed systems, but on the whole the results tend to support the lensing model estimates of the magnification. Our result indicates that the amplification can be independently measured using the L - σ relation in lensed giant HII regions or HII galaxies. It also supports the suggestion, even if lensing is model dependent, that the L - σ relation is valid for low luminosity high-z objects. Ad hoc observations of lensed star-forming systems are required to determine the lensing amplification accurately.

  18. The Vela Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Raymond, John C.

    We wish to obtain both emission and absorption line observations of the Vela Supernova remnant. The filament we wish to study in emission is the brightest filament in the SNR, so it will provide a spectrum twice the quality of any in existence. It is also located at the edge of an unusual bulge in the SNR, and it can be used to test the level of departure from pressure equilibrium in the remnant, which is useful as a test of evaporative models of SNR evolution. The absorption line studies will look for evidence of the drastically unstable behavior of shocks above 150 km/s predicted by Innes and Giddings. Four of the stars studied by Jenkins, Silk and Wallerstein showed marginal evidence for two positive or two negative high velocity components. If these multiple velocity components are confirmed, they support the secondary shock predictions of Innes and Giddings.

  19. Pulsars and supernova remnants

    SciTech Connect

    Narayan, R.; Schaudt, K.J.

    1988-02-01

    With the recent discovery of the pulsar PSR 1951 + 22 in CTB 80, four pulsars are now known in supernova remnants (SNRs) of the plerion and composite classes. It is argued that this success rate of pulsar detections implies that young fast pulsars have long fan-beams that enable them to be seen from most directions. Based on calculations that use a pulsar luminosity model and allow for selection effects, it is suggested that the best SNRs for future pulsar searches are 3C 58, MSH 11-62, G24.7 + 0.6, and MSH 15-56. It is also concluded that the failure to detect pulsars in shell SNRs implies either that there are no pulsars in these SNRs or that the pulsars are unusually weak, possibly due to slow rotation or weak magnetic fields. 25 references.

  20. Supernova Candidate from CSS

    NASA Astrophysics Data System (ADS)

    Drake, A. J.; Mahabal, A.; Djorgovski, S. G.; Williams, R.; Graham, M. J.; Christensen, E.; Beshore, E. C.; Larson, S. M.

    2008-06-01

    We have detected a likely Supernova in Catalina Sky Survey images from 11 Jun 2008 UT. The object has the following parameters:

    CSS080611:121642+410211 2008-06-11 UT 04:52:41 RA 12:16:41.53 Dec 41:02:11.2 Mag 17.7 Type SN
    The object is near the edge of galaxy SDSSJ121642.18+410223.7 (z = 0.039, mags: g~ 17.9, r~17.6, i~17.3, z~17.5).

  1. Supernova olivine from cometary dust.

    PubMed

    Messenger, Scott; Keller, Lindsay P; Lauretta, Dante S

    2005-07-29

    An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (<0.8 times solar), indicative of formation from a type II supernova. The aggregate contains olivine (forsterite 83) grains <100 nanometers in size, with microstructures that are consistent with minimal thermal alteration. This unusually iron-rich olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.

  2. Supernova olivine from cometary dust

    NASA Technical Reports Server (NTRS)

    Messenger, Scott; Keller, Lindsay P.; Lauretta, Dante S.

    2005-01-01

    An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (<0.8 times solar), indicative of formation from a type II supernova. The aggregate contains olivine (forsterite 83) grains <100 nanometers in size, with microstructures that are consistent with minimal thermal alteration. This unusually iron-rich olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.

  3. Dimming supernovae without cosmic acceleration.

    PubMed

    Csáki, Csaba; Kaloper, Nemanja; Terning, John

    2002-04-22

    We present a simple model where photons propagating in extragalactic magnetic fields can oscillate into very light axions. The oscillations may convert some of the photons, departing a distant supernova, into axions, making the supernova appear dimmer and hence more distant than it really is. Averaging over different configurations of the magnetic field we find that the dimming saturates at about one-third of the light from the supernovae at very large redshifts. This results in a luminosity distance versus redshift curve almost indistinguishable from that produced by the accelerating Universe, if the axion mass and coupling scale are m approximately 10(-16) eV, M approximately 4 x 10(11) GeV. This phenomenon may be an alternative to the accelerating Universe for explaining supernova observations.

  4. Spectroscopic classification of supernova candidates

    NASA Astrophysics Data System (ADS)

    Hodgkin, S. T.; Hall, A.; Fraser, M.; Campbell, H.; Wyrzykowski, L.; Kostrzewa-Rutkowska, Z.; Pietro, N.

    2014-09-01

    We report the spectroscopic classification of four supernovae at the 2.5m Isaac Newton Telescope on La Palma, using the Intermediate Dispersion Spectrograph and the R300V grating (3500-8000 Ang; ~6 Ang resolution).

  5. Simulation of Kepler Supernova Explosion

    NASA Video Gallery

    This video shows a simulation of the Kepler supernova as it interacts with material expelled by the giant star companion to the white dwarf before the latter exploded. It was assumed that the bulk ...

  6. [Reducing the searching range of supernova candidates automatically in a flood of spectra of galaxies].

    PubMed

    Tu, Liang-Ping; Luo, A-Li; Wu, Fu-Chao; Zhao, Yong-Heng

    2009-12-01

    Supernova (SN) is one of the most intense astronomical phenomena among the known stellar activities, but compared with several billion astronomical objects which people have probed, the number of supernova the authors have observed is very small. Therefore, the authors need to find faster and higher-efficiency approaches to searching supernova. In the present paper, we present a novel automated method, which can be successfully used to reduce the range of searching for 1a supernova candidates in a huge number of galaxy spectra. The theoretical basis of the method is clustering and outlier picking, by introducing and measuring local outlier factors of data samples, description of statistic characters of SN emerges in low dimension space. Firstly, eigenvectors of Peter's 1a supernova templates are acquired through PCA projection, and the description of la supernova's statistic characters is calculated. Secondly, in all data set, the local outlier factor (LOF) of each galaxy is calculated including those SN and their host galaxy spectra, and all LOFs are arranged in descending order. Finally, spectra with the largest first one percent of all LOFs should be the reduced 1a SN candidates. Experiments show that this method is a robust and correct range reducing method, which can get rid of the galaxy spectra without supernova component automatically in a flood of galaxy spectra. It is a highly efficient approach to getting the reliable candidates in a spectroscopy survey for follow-up photometric observation.

  7. Supernova Modeling: Progress and Challenges

    SciTech Connect

    Cardall, Christian Y

    2012-01-01

    Neutrinos play important roles in the pre-collapse evolution, explosion, and aftermath of core-collapse supernovae. Detected neutrino signals from core-collapse supernovae would provide insight into the explosion mechanism and unknown neutrino mixing parameters. Achieving these goals requires large-scale, multiphysics simulations. For many years, several groups have performed such simulations with increasing realism. Current simulations and plans for future work of the Oak Ridge group are described.

  8. A spatial, kinematical, and dynamical analysis of Abell 400

    NASA Technical Reports Server (NTRS)

    Beers, Timothy C.; Gebhardt, Karl; Huchra, John P.; Forman, William; Jones, Christine; Bothun, Gregory D.

    1992-01-01

    The paper presents a detailed spatial, kinematical, and dynamical analysis for the cluster A400, based on a nearly complete redshift survey of bright galaxies within 1 Mpc of the cluster center. A dispersed component with a high fraction of spiral galaxies at a velocity of 8200 km/s, and a background group with a mean velocity of 13,400 km/s are identified. It is proposed that the main body of A400 is composed of at least two individual subclusters. If subclustering is ignored, the derived dispersion of the 88 galaxies with measured velocities within 4000 km/s of the bright dumbbell galaxy near the cluster center is 702 km/s. When kinematic information is used to split A400 into likely subclusters, the velocity dispersions of the individual units which make up this cluster are on the order of 200-300 km/s. If A400 is considered a single entity, the inferred blue mass-to-light ratio is 1210 solar masses/solar luminosities. It is argued that A400 is an example of a presently occurring merger, and that the individual components of the dumbbell galaxy were once individual D galaxies within the premerger subclusters.

  9. Distant Supernovae Indicate Ever-Expanding Universe

    NASA Astrophysics Data System (ADS)

    1998-12-01

    parameters, the age of the Universe and the geometry of space can be derived. They have been the focus of a large number of astronomical programmes over the past decades. Many aspects of the currently preferred cosmological model, the Hot Big Bang , have been impressively confirmed by observations of the expansion of the Universe, the cosmic background radiation, and also the explanation of the synthesis of light elements. Still, our knowledge about the dynamical state of the Universe, as well as the early formation of structures, i.e., of galaxies and stars, is far from complete - this remains a field of active research. Possibly, the simplest way to test our present assumptions in this direction is to measure accurate distances and compare them with the expected cosmic scale. This is where the recent results contribute to our understanding of the Universe. The key role of supernovae The two research teams, both with participation from ESO [1], have concentrated on the study of rare stellar explosions, during which certain old stars undergo internal incineration. In this process, explosive nuclear fusion burns matter into the most stable atomic nucleus, iron, and releases a gigantic amount of energy. ESO PR Photo 50a/98 ESO PR Photo 50a/98 [Preview - JPEG: 800 x 648 pix - 768k] [High-Res - JPEG: 3000 x 2431 pix - 8.5Mb] ESO PR Photo 50b/98 ESO PR Photo 50b/98 [Preview - JPEG: 800 x 649 pix - 784k] [High-Res - JPEG: 3000 x 2432 pix - 8.4Mb] These photos illustrate the follow-up observations on which the new results described in this Press Release are based. Sky fields with clusters of galaxies are monitored with the 4-m telescope at Cerro Tololo Interamerican Observatory (CTIO) in Chile and spectra are obtained of suddenly appearing star-like objects that may be supernovae. Confirmed Type Ia supernovae are then monitored by ESO telescopes at La Silla and at other observatories. In PR Photo 50a/98 , a supernova at redshift z = 0.51 [2] (corresponding to a distance of about 10

  10. Ozone Depletion from Nearby Supernovae

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  11. The Early-type Galaxy Population in Abell 2390

    NASA Astrophysics Data System (ADS)

    Fritz, A.; Ziegler, B. L.

    We present high-quality spectroscopic data of 51 elliptical and lenticular galaxies in the rich cluster A2390 at z=0.23 obtained with MOSCA from the 3.5 m telescope at the Calar Alto Observatory in 7 nights during 2 runs. Our investigation is spanning a wider range in luminosity (M*B+1) than previous spectroscopic studies, which were limited to a small number of the more luminous galaxies. This is only the second cluster at intermediate redshift where such a large sample has been investigated (the other is A2218 at z=0.18, see Ziegler et al. MNRAS 2001, in press, astro-ph/0103475). Analysis of absorption line strengths lets us explore the evolution of galaxies in age and metallicity. Velocity dispersions (σ) are determined to study the slope, scatter and zeropoint offset of the Faber-Jackson and Mg-σ relations. In combination with morphological and structural parameters of a subsample of galaxies observed with HST, we also investigate the evolution of the Fundamental Plane. The overall sample is large enough to explore statistically significant sub-populations like S0 or Balmer-line enhanced galaxies and look for variations in early-type galaxy evolution as a function of distance from the cluster center. In addition to studying the evolution with respect to local clusters, we also investigate the variations in slope, scatter and zeropoint of the above relations between the equally rich clusters A2218 and A2390 at z=0.2.

  12. First supernova companion star found

    NASA Astrophysics Data System (ADS)

    2004-01-01

    Supernova 1993J exploding hi-res Size hi-res: 222 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Supernova 1993J exploding (artist’s impression) New observations with the Hubble Space Telescope allow a look into a supernova explosion under development. In this artist’s view the red supergiant supernova progenitor star (left) is exploding after having transferred about 10 solar masses of hydrogen gas to the blue companion star (right). This interaction process happened over about 250 years and affected the supernova explosion to such an extent that SN 1993J was later known as one of the most peculiar supernovae ever seen. Supernova 1993J exploding hi-res Size hi-res: 4200 kb Credits: ESA and Justyn R. Maund (University of Cambridge) The site of the Supernova 1993J explosion A virtual journey into one of the spiral arms of the grand spiral Messier 81 (imaged with the Isaac Newton Telescope on La Palma, left) reveals the superb razor-sharp imaging power of the NASA/ESA Hubble Space Telescope (Hubble’s WFPC2 instrument, below). The close-up (with Hubble’s ACS, to the right) is centred on the newly discovered companion star to Supernova 1993J that itself is no longer visible. The quarter-circle around the supernova companion is a so-called light echo originating from sheets of dust in the galaxy reflecting light from the original supernova explosion. Supernova 1993J explosing site hi-res Size hi-res: 1502 kb Credits: ESA and Justyn R. Maund (University of Cambridge) Close-up of the Supernova 1993J explosion site (ACS/HRC image) This NASA/ESA Hubble Space Telescope image shows the area in Messier 81 where Supernova 1993J exploded. The companion to the supernova ‘mother star’ that remains after the explosion is seen in the centre of the image. The image is taken with Hubble’s Advanced Camera for Surveys and is a combination of four exposures taken with ACS’ High Resolution Camera. The exposures were taken through two near-UV filters (250W

  13. AGN Feedback in Clusters of Galaxies

    DTIC Science & Technology

    2010-01-01

    bubbles created by the radio lobes evacuating regions of the ICM vary widely from a few kpc (e.g. Abell 262 [21, 22]) to hundreds of kpc (e.g. MS0735.6...diameters of approximately 200 kpc . The total energy injection required to inflate the cavities and produce the ob- served shocks is 6 × 1061 erg...cluster center, and these are modeled as shocks in [32] based on the earlier 163 ksec dataset. These features are at 31 and 46 kpc from the AGN and the

  14. Complete Measurement of S(1D2) Photofragment Alignment from Abel-Invertible Ion Images

    NASA Astrophysics Data System (ADS)

    Rakitzis, T. Peter; Samartzis, Peter C.; Kitsopoulos, Theofanis N.

    2001-09-01

    A novel method to measure directly the photofragment alignment from Abel-invertible two-dimensional ion images, as a function of photofragment recoil velocity, is demonstrated for S(1D2) atoms from the photodissociation of carbonyl sulfide at 223 nm. The results are analyzed in terms of coherent and incoherent contributions from two dissociative states, showing that the phase differences of the asymptotic wave functions of the fast and slow recoil-velocity channel are approximately π/2 and 0, respectively.

  15. Serre duality, Abel's theorem, and Jacobi inversion for supercurves over a thick superpoint

    NASA Astrophysics Data System (ADS)

    Rothstein, Mitchell J.; Rabin, Jeffrey M.

    2015-04-01

    The principal aim of this paper is to extend Abel's theorem to the setting of complex supermanifolds of dimension 1 | q over a finite-dimensional local supercommutative C-algebra. The theorem is proved by establishing a compatibility of Serre duality for the supercurve with Poincaré duality on the reduced curve. We include an elementary algebraic proof of the requisite form of Serre duality, closely based on the account of the reduced case given by Serre in Algebraic groups and class fields, combined with an invariance result for the topology on the dual of the space of répartitions. Our Abel map, taking Cartier divisors of degree zero to the dual of the space of sections of the Berezinian sheaf, modulo periods, is defined via Penkov's characterization of the Berezinian sheaf as the cohomology of the de Rham complex of the sheaf D of differential operators. We discuss the Jacobi inversion problem for the Abel map and give an example demonstrating that if n is an integer sufficiently large that the generic divisor of degree n is linearly equivalent to an effective divisor, this need not be the case for all divisors of degree n.

  16. SAS 3 and related observations of Abell 2029

    NASA Technical Reports Server (NTRS)

    Johnson, H. M.; Schnopper, H. W.; Delvaille, J. P.

    1980-01-01

    X-ray and radio observations of the cluster of galaxies show that the central cD galaxy dominates the emissions. Resolution of the X-ray source shows that its extent is significantly greater than that of the profile of surface brightness of the cD galaxy. Dressler's model of most of the cluster mass with very high M/L(v) is similarly extended. The optically dark mass may provide low-energy X-ray emission of the coronae of 5 x 10 to the 16th stars with very high M/L(v), but in the 2-10 keV range the data are consistent with current theoretical predictions for hot intracluster gas.

  17. The Search for Lensed Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-01-01

    Type Ia supernovae that have multiple images due to gravitational lensing can provide us with a wealth of information both about the supernovae themselves and about our surrounding universe. But how can we find these rare explosions?Clues from Multiple ImagesWhen light from a distant object passes by a massive foreground galaxy, the galaxys strong gravitational pull can bend the light, distorting our view of the backgroundobject. In severe cases, this process can cause multiple images of the distant object to appear in the foreground lensing galaxy.An illustration of gravitational lensing. Light from the distant supernova is bent as it passes through a giant elliptical galaxy in the foreground, causing multiple images of the supernova to appear to be hosted by the elliptical galaxy. [Adapted from image by NASA/ESA/A. Feild (STScI)]Observations of multiply-imaged Type Ia supernovae (explosions that occur when white dwarfs in binary systems exceed their maximum allowed mass) could answer a number of astronomical questions. Because Type Ia supernovae are standard candles, distant, lensed Type Ia supernovae can be used to extend the Hubble diagram to high redshifts. Furthermore, the lensing time delays from the multiply-imaged explosion can provide high-precision constraints on cosmological parameters.The catch? So far, weve only found one multiply-imaged Type Ia supernova: iPTF16geu, discovered late last year. Were going to need a lot more of them to develop a useful sample! So how do we identify themutiply-imaged Type Ias among the many billions of fleeting events discovered in current and future surveys of transients?Searching for AnomaliesAbsolute magnitudes for Type Ia supernovae in elliptical galaxies. None are expected to be above -20 in the B band, so if we calculate a magnitude for a Type Ia supernova thats larger than this, its probably not hosted by the galaxy we think it is! [Goldstein Nugent 2017]Two scientists from University of California, Berkeley and

  18. How Bright Can Supernovae Get?

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-04-01

    Supernovae enormous explosions associated with the end of a stars life come in a variety of types with different origins. A new study has examined how the brightest supernovae in the Universe are produced, and what limits might be set on their brightness.Ultra-Luminous ObservationsRecent observations have revealed many ultra-luminous supernovae, which haveenergies that challenge our abilities to explain them usingcurrent supernova models. An especially extreme example is the 2015 discovery of the supernova ASASSN-15lh, which shone with a peak luminosity of ~2*1045 erg/s, nearly a trillion times brighter than the Sun. ASASSN-15lh radiated a whopping ~2*1052 erg in the first four months after its detection.How could a supernova that bright be produced? To explore the answer to that question, Tuguldur Sukhbold and Stan Woosley at University of California, Santa Cruz, have examined the different sources that could produce supernovae and calculated upper limits on the potential luminosities ofeach of these supernova varieties.Explosive ModelsSukhbold and Woosley explore multiple different models for core-collapse supernova explosions, including:Prompt explosionA stars core collapses and immediately explodes.Pair instabilityElectron/positron pair production at a massive stars center leads to core collapse. For high masses, radioactivity can contribute to delayed energy output.Colliding shellsPreviously expelled shells of material around a star collide after the initial explosion, providing additional energy release.MagnetarThe collapsing star forms a magnetar a rapidly rotating neutron star with an incredibly strong magnetic field at its core, which then dumps energy into the supernova ejecta, further brightening the explosion.They then apply these models to different types of stars.Setting the LimitThe authors show that the light curve of ASASSN-15lh (plotted in orange) can be described by a model (black curve) in which a magnetar with an initial spin period of 0.7 ms

  19. The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry

    SciTech Connect

    Miknaitis, Gajus; Pignata, G.; Rest, A.; Wood-Vasey, W.M.; Blondin, S.; Challis, P.; Smith, R.C.; Stubbs, C.W.; Suntzeff, N.B.; Foley, R.J.; Matheson, T.; Tonry, J.L.; Aguilera, C.; Blackman, J.W.; Becker, A.C.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Filippenko, A.V.; Garg, A.; Garnavich, P.M.; /Fermilab /Chile U., Catolica /Cerro-Tololo InterAmerican Obs. /Harvard-Smithsonian Ctr. Astrophys. /Harvard U. /UC, Berkeley, Astron. Dept. /NOAO, Tucson /Inst. Astron., Honolulu /Res. Sch. Astron. Astrophys., Weston Creek /Washington U., Seattle, Astron. Dept. /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /Ohio State U., Dept. Astron. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Stockholm U.

    2007-01-08

    We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the equation of state parameter of the dark energy. We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to the dark energy equation of state parameter w = P/{rho}c{sup 2} for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z {approx} 0.5 {+-} 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4m natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 type Ia SNe, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for the all type Ia supernovae found by ESSENCE and used in our measurement of w, presented in Wood-Vasey et al. (2007).

  20. The Richness Dependence of Galaxy Cluster Correlations: Results From A Redshift Survey Of Rich APM Clusters

    NASA Technical Reports Server (NTRS)

    Croft, R. A. C.; Dalton, G. B.; Efstathiou, G.; Sutherland, W. J.; Maddox, S. J.

    1997-01-01

    We analyze the spatial clustering properties of a new catalog of very rich galaxy clusters selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell Richness Class greater than or equal to 1 clusters, but selected using an objective algorithm from a catalog demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function xi(sub cc)(r) for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maximum likelihood estimator to find the best fitting slope and amplitude of a power law fit to x(sub cc)(r), and to estimate the correlation length r(sub 0) (the value of r at which xi(sub cc)(r) is equal to unity). For clusters with a mean space density of 1.6 x 10(exp -6) h(exp 3) MpC(exp -3) (equivalent to the space density of Abell Richness greater than or equal to 2 clusters), we find r(sub 0) = 21.3(+11.1/-9.3) h(exp -1) Mpc (95% confidence limits). This is consistent with the weak richness dependence of xi(sub cc)(r) expected in Gaussian models of structure formation. In particular, the amplitude of xi(sub cc)(r) at all richnesses matches that of xi(sub cc)(r) for clusters selected in N-Body simulations of a low density Cold Dark Matter model.

  1. Superluminous Extragalactic Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Chen, C. H. R.; Chu, Y.-H.

    1998-12-01

    Extragalactic supernova remnants (SNRs) are conventionally surveyed by optical emission-line images, using the [S II]/Hα line ratio to diagnose SNRs. The majority of the optically identified extragalactic SNRs are too faint to be confirmed at X-ray or radio wavelengths. Conversely, extragalactic SNRs that are initially identified by X-ray or radio observations are all superluminous, e.g., the X-ray SNR in NGC 6946 (Blair & Fesen 1994, ApJ, 424, L103) and the radio SNR in NGC 5471 (Skillman 1985, ApJ, 290, 449). NGC 5471 is a giant H II region in M101. Optical echelle observations of the SNR in NGC 5471 have detected high-velocity gas with a FWZI of at least 350 km/s. Decomposing the narrow H II component and the broad SNR component in the Hα velocity profile, Chu & Kennicutt (1986) derived a total mass of 6500+/-3000 M_sun and a kinetic energy of a few *E(50) ergs. Using archival ROSAT X-ray observations, Williams & Chu (1995) measured an X-ray luminosity of ~ 1 x 10(38) ergs/s for NGC 5471. Apparently, the SNR in NGC 5471 is superluminous at all wavelengths. To determine the physical conditions and nature of the superluminous SNR in NGC 5471, we have obtained HST WFPC2 images of NGC 5471 in the Hα and [S II] lines and two continuum bands. These high-resolution images reveal a [S II]-enhanced shell with a diameter of ~ 60 pc. A recent 180-ks ROSAT High Resolution Imager image of M101 shows that the X-ray emission from NGC 5471 peaks at this SNR shell. We are thus confident in the identification of the superluminous SNR in NGC 5471. Are superluminous SNRs produced by particularly powerful supernova explosions? Are they associated with gamma-ray bursters? Are their luminosities caused by dense interstellar environment? We will report the detailed physical properties of the SNR in NGC 5471, compare it to the other superluminous SNRs, and address these questions.

  2. Supernova Explosions Stay In Shape

    NASA Astrophysics Data System (ADS)

    2009-12-01

    At a very early age, children learn how to classify objects according to their shape. Now, new research suggests studying the shape of the aftermath of supernovas may allow astronomers to do the same. A new study of images from NASA's Chandra X-ray Observatory on supernova remnants - the debris from exploded stars - shows that the symmetry of the remnants, or lack thereof, reveals how the star exploded. This is an important discovery because it shows that the remnants retain information about how the star exploded even though hundreds or thousands of years have passed. "It's almost like the supernova remnants have a 'memory' of the original explosion," said Laura Lopez of the University of California at Santa Cruz, who led the study. "This is the first time anyone has systematically compared the shape of these remnants in X-rays in this way." Astronomers sort supernovas into several categories, or "types", based on properties observed days after the explosion and which reflect very different physical mechanisms that cause stars to explode. But, since observed remnants of supernovas are leftover from explosions that occurred long ago, other methods are needed to accurately classify the original supernovas. Lopez and colleagues focused on the relatively young supernova remnants that exhibited strong X-ray emission from silicon ejected by the explosion so as to rule out the effects of interstellar matter surrounding the explosion. Their analysis showed that the X-ray images of the ejecta can be used to identify the way the star exploded. The team studied 17 supernova remnants both in the Milky Way galaxy and a neighboring galaxy, the Large Magellanic Cloud. For each of these remnants there is independent information about the type of supernova involved, based not on the shape of the remnant but, for example, on the elements observed in it. The researchers found that one type of supernova explosion - the so-called Type Ia - left behind relatively symmetric, circular

  3. Light-echo spectroscopy of historic Supernovae

    NASA Astrophysics Data System (ADS)

    Krause, Oliver

    Young Galactic supernova remnants are unique laboratories for supernova physics. Due to their proximity they provide us with the most detailed view of the outcome of a supernova. However, the exact spectroscopic types of their original explosions have been undetermined so far -hindering to link the wealth of multi-wavelength knowledge about their remnants with the diverse population of supernovae. Light echoes, reflektions of the brilliant supernova burst of light by interstellar dust, provide a unique opportunity to reobserve today -with powerful scientific instruments of the 21st century -historic supernova exlosions even after hundreds of years and to conclude on their nature. We report on optical light-echo spectroscopy of two famous Galactic supernovae: Tycho Brahe's SN 1572 and the supernova that created the Cassiopeia A remnant around the year 1680. These observations finally recovered the missing spectroscopic classifications and provide new constraints on explosion models for future studies.

  4. Probing single biomolecules in solution using the Anti-Brownian ELectrokinetic (ABEL) trap

    PubMed Central

    Wang, Quan; Goldsmith, Randall H.; Jiang, Yan; Bockenhauer, Samuel D.; Moerner, W.E.

    2012-01-01

    Conspectus Single-molecule fluorescence measurements allow researchers to study asynchronous dynamics and expose molecule-to-molecule structural and behavioral diversity, which contributes to the understanding of biological macromolecules. To provide measurements that are most consistent with the native environment of biomolecules, researchers would like to conduct these measurements in the solution phase if possible. However, diffusion typically limits the observation time to approximately one millisecond in many solution-phase single-molecule assays. Although surface immobilization is widely used to address this problem, this process can perturb the system being studied and contribute to the observed heterogeneity. Combining the technical capabilities of high-sensitivity single-molecule fluorescence microscopy, realtime feedback control and electrokinetic flow in a microfluidic chamber, we have developed a device called the Anti-Brownian ELectrokinetic (ABEL) trap to significantly prolong the observation time of single biomolecules in solution. We have applied the ABEL trap method to explore the photodynamics and enzymatic properties of a variety of biomolecules in aqueous solution and present four examples: the photosynthetic antenna allophycocyanin, the chaperonin enzyme TRiC, a G protein-coupled receptor protein, and the blue nitrite reductase redox enzyme. These examples illustrate the breadth and depth of information which we can extract in studies of single biomolecules with the ABEL trap. When confined in the ABEL trap, the photosynthetic antenna protein allophycocyanin exhibits rich dynamics both in its emission brightness and its excited state lifetime. As each molecule discontinuously converts from one emission/lifetime level to another in a primarily correlated way, it undergoes a series of state changes. We studied the ATP binding stoichiometry of the multi-subunit chaperonin enzyme TRiC in the ABEL trap by counting the number of hydrolyzed Cy3-ATP

  5. Probing single biomolecules in solution using the anti-Brownian electrokinetic (ABEL) trap.

    PubMed

    Wang, Quan; Goldsmith, Randall H; Jiang, Yan; Bockenhauer, Samuel D; Moerner, W E

    2012-11-20

    Single-molecule fluorescence measurements allow researchers to study asynchronous dynamics and expose molecule-to-molecule structural and behavioral diversity, which contributes to the understanding of biological macromolecules. To provide measurements that are most consistent with the native environment of biomolecules, researchers would like to conduct these measurements in the solution phase if possible. However, diffusion typically limits the observation time to approximately 1 ms in many solution-phase single-molecule assays. Although surface immobilization is widely used to address this problem, this process can perturb the system being studied and contribute to the observed heterogeneity. Combining the technical capabilities of high-sensitivity single-molecule fluorescence microscopy, real-time feedback control and electrokinetic flow in a microfluidic chamber, we have developed a device called the anti-Brownian electrokinetic (ABEL) trap to significantly prolong the observation time of single biomolecules in solution. We have applied the ABEL trap method to explore the photodynamics and enzymatic properties of a variety of biomolecules in aqueous solution and present four examples: the photosynthetic antenna allophycocyanin, the chaperonin enzyme TRiC, a G protein-coupled receptor protein, and the blue nitrite reductase redox enzyme. These examples illustrate the breadth and depth of information which we can extract in studies of single biomolecules with the ABEL trap. When confined in the ABEL trap, the photosynthetic antenna protein allophycocyanin exhibits rich dynamics both in its emission brightness and its excited state lifetime. As each molecule discontinuously converts from one emission/lifetime level to another in a primarily correlated way, it undergoes a series of state changes. We studied the ATP binding stoichiometry of the multi-subunit chaperonin enzyme TRiC in the ABEL trap by counting the number of hydrolyzed Cy3-ATP using stepwise

  6. Supernovae. Old supernova dust factory revealed at the Galactic center.

    PubMed

    Lau, R M; Herter, T L; Morris, M R; Li, Z; Adams, J D

    2015-04-24

    Dust formation in supernova ejecta is currently the leading candidate to explain the large quantities of dust observed in the distant, early universe. However, it is unclear whether the ejecta-formed dust can survive the hot interior of the supernova remnant (SNR). We present infrared observations of ~0.02 solar masses of warm (~100 kelvin) dust seen near the center of the ~10,000-year-old Sagittarius A East SNR at the Galactic center. Our findings indicate the detection of dust within an older SNR that is expanding into a relatively dense surrounding medium (electron density ~10(3) centimeters(-3)) and has survived the passage of the reverse shock. The results suggest that supernovae may be the dominant dust-production mechanism in the dense environment of galaxies of the early universe.

  7. The Shape of Superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    What causes the tremendous explosions of superluminous supernovae? New observations reveal the geometry of one such explosion, SN 2015bn, providing clues as to its source.A New Class of ExplosionsImage of a type Ia supernova in the galaxy NGC 4526. [NASA/ESA]Supernovae are powerful explosions that can briefly outshine the galaxies that host them. There are several different classifications of supernovae, each with a different physical source such as thermonuclear instability in a white dwarf, caused by accretion of too much mass, or the exhaustion of fuel in the core of a massive star, leading to the cores collapse and expulsion of its outer layers.In recent years, however, weve detected another type of supernovae, referred to as superluminous supernovae. These particularly energetic explosions last longer months instead of weeks and are brighter at their peaks than normal supernovae by factors of tens to hundreds.The physical cause of these unusual explosions is still a topic of debate. Recently, however, a team of scientists led by Cosimo Inserra (Queens University Belfast) has obtained new observations of a superluminous supernova that might help address this question.The flux and the polarization level (black lines) along the dominant axis of SN 2015bn, 24 days before peak flux (left) and 28 days after peak flux (right). Blue lines show the authors best-fitting model. [Inserra et al. 2016]Probing GeometryInserra and collaborators obtained two sets of observations of SN 2015bn one roughly a month before and one a month after the superluminous supernovas peak brightness using a spectrograph on the Very Large Telescope in Chile. These observations mark the first spectropolarimetric data for a superluminous supernova.Spectropolarimetry is the practice of obtaining information about the polarization of radiation from an objects spectrum. Polarization carries information about broken spatial symmetries in the object: only if the object is perfectly symmetric can it

  8. A Supernova's Shockwaves

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Supernovae are the explosive deaths of the universe's most massive stars. In death, these volatile creatures blast tons of energetic waves into the cosmos, destroying much of the dust surrounding them.

    This false-color composite from NASA's Spitzer Space Telescope and NASA's Chandra X-ray Observatory shows the remnant of one such explosion. The remnant, called N132D, is the wispy pink shell of gas at the center of this image. The pinkish color reveals a clash between the explosion's high-energy shockwaves and surrounding dust grains.

    In the background, small organic molecules called polycyclic aromatic hydrocarbons are shown as tints of green. The blue spots represent stars in our galaxy along this line of sight.

    N132D is located 163,000 light-years away in a neighboring galaxy called, the Large Magellanic Cloud.

    In this image, infrared light at 4.5 microns is mapped to blue, 8.0 microns to green and 24 microns to red. Broadband X-ray light is mapped purple. The infrared data were taken by Spitzer's infrared array camera and multiband imaging photometer, while the X-ray data were captured by Chandra.

  9. Supernova Remnants And GLAST

    SciTech Connect

    Slane, Patrick; /Harvard-Smithsonian Ctr. Astrophys.

    2011-11-29

    It has long been speculated that supernova remnants represent a major source of cosmic rays in the Galaxy. Observations over the past decade have ceremoniously unveiled direct evidence of particle acceleration in SNRs to energies approaching the knee of the cosmic ray spectrum. Nonthermal X-ray emission from shell-type SNRs reveals multi-TeV electrons, and the dynamical properties of several SNRs point to efficient acceleration of ions. Observations of TeV gamma-ray emission have confirmed the presence of energetic particles in several remnants as well, but there remains considerable debate as to whether this emission originates with high energy electrons or ions. Equally uncertain are the exact conditions that lead to efficient particle acceleration. Based on the catalog of EGRET sources, we know that there is a large population of Galactic gamma-ray sources whose distribution is similar to that of SNRs.With the increased resolution and sensitivity of GLAST, the gamma-ray SNRs from this population will be identified. Their detailed emission structure, along with their spectra, will provide the link between their environments and their spectra in other wavebands to constrain emission models and to potentially identify direct evidence of ion acceleration in SNRs. Here I summarize recent observational and theoretical work in the area of cosmic ray acceleration by SNRs, and discuss the contributions GLAST will bring to our understanding of this problem.

  10. Supernova explosions in the Universe.

    PubMed

    Burrows, A

    2000-02-17

    During the lifetime of our Milky Way galaxy, there have been something like 100 million supernova explosions, which have enriched the Galaxy with the oxygen we breathe, the iron in our cars, the calcium in our bones and the silicon in the rocks beneath our feet. These exploding stars also influence the birth of new stars and are the source of the energetic cosmic rays that irradiate us on the Earth. The prodigious amount of energy (approximately 10(51), or approximately 2.5 x 10(28) megatonnes of TNT equivalent) and momentum associated with each supernova may even have helped to shape galaxies as they formed in the early Universe. Supernovae are now being used to measure the geometry of the Universe, and have recently been implicated in the decades-old mystery of the origin of the gamma-ray bursts. Together with major conceptual advances in our theoretical understanding of supernovae, these developments have made supernovae the centre of attention in astrophysics.

  11. Theory and phenomenology of supernova neutrinos

    SciTech Connect

    Lunardini, Cecilia

    2015-07-15

    The theory and phenomenology of supernova neutrinos is reviewed, with focus on the most recent advancements on the neutrino flux predicted by supernova numerical models, on neutrino oscillations inside the star and in the Earth, and on the physics of the diffuse supernova neutrino background. Future directions of research are briefly summarized.

  12. A very faint core-collapse supernova in M85.

    PubMed

    Pastorello, A; Della Valle, M; Smartt, S J; Zampieri, L; Benetti, S; Cappellaro, E; Mazzali, P A; Patat, F; Spiro, S; Turatto, M; Valenti, S

    2007-10-18

    An anomalous transient in the early Hubble-type (S0) galaxy Messier 85 (M85) in the Virgo cluster was discovered by Kulkarni et al. on 7 January 2006 that had very low luminosity (peak absolute R-band magnitude M(R) of about -12) that was constant over more than 80 days, red colour and narrow spectral lines, which seem inconsistent with those observed in any known class of transient events. Kulkarni et al. suggest an exotic stellar merger as the possible origin. An alternative explanation is that the transient in M85 was a type II-plateau supernova of extremely low luminosity, exploding in a lenticular galaxy with residual star-forming activity. This intriguing transient might be the faintest supernova that has ever been discovered.

  13. Learning from the scatter in type ia supernovae

    SciTech Connect

    Dodelson, Scott; Vallinotto, Alberto; /Fermilab /Chicago U.

    2005-11-01

    Type Ia Supernovae are standard candles so their mean apparent magnitude has been exploited to learn about the redshift-distance relationship. Besides intrinsic scatter in this standard candle, additional scatter is caused by gravitational magnification by large scale structure. Here they probe the dependence of this dispersion on cosmological parameters and show that information about the amplitude of clustering, {sigma}{sub s}, is contained in the scatter. In principle, it will be possible to constrain {sigma}{sub s} to within 5% with observations of 2000 Type Ia Supernovae. They identify three sources of systematic error--evolution of intrinsic scatter, baryon contributions to lensing, and non-Gaussianity of lensing--which will make this measurement difficult.

  14. The Cluster of Galaxies Surrounding Cygnus A

    NASA Astrophysics Data System (ADS)

    Owen, Frazer N.; Ledlow, Michael J.; Morrison, Glenn E.; Hill, John M.

    1997-10-01

    We report optical imaging and spectroscopy of 41 galaxies in a 22' square region surrounding Cygnus A. The results show that there is an extensive rich cluster associated with Cyg A of Abell richness of at least 1 and possibly as high as 4. The velocity histogram has two peaks, one centered on Cyg A and a more significant peak redshifted by about 2060 km s-1 from the velocity of Cyg A. The dynamical centroid of the spatial distribution is also shifted somewhat to the northwest. However, statistical tests show only weak evidence that there are two distinct clusters. The entire system has a velocity dispersion of 1581 km s-1, which is slightly larger than other, well-studied examples of rich clusters.

  15. The evolution of red supergiants to supernova in NGC 2100

    NASA Astrophysics Data System (ADS)

    Beasor, Emma R.; Davies, Ben

    2016-12-01

    The mass-loss rates of red supergiants (RSGs) govern their evolution towards supernova and dictate the appearance of the resulting explosion. To study how mass-loss rates change with evolution, we measure the mass-loss rates (dot{M}) and extinctions of 19 RSGs in the young massive cluster NGC 2100 in the Large Magellanic Cloud. By targeting stars in a coeval cluster, we can study the mass-loss rate evolution whilst keeping the variables of mass and metallicity fixed. Mass-loss rates were determined by fitting DUSTY models to mid-IR photometry from WISE and Spitzer/IRAC. We find that the dot{M} in RSGs increases as the star evolves, and is well described by dot{M} prescription of de Jager, used widely in stellar evolution calculations. We find that the extinction caused by the warm dust is negligible, meaning the warm circumstellar material of the inner wind cannot explain the higher levels of extinction found in the RSGs compared to other cluster stars. We discuss the implications of this work in terms of supernova progenitors and stellar evolution theory. We argue that there is little justification for substantially increasing the dot{M} during the RSG phase, as has been suggested recently in order to explain the absence of high-mass Type IIP supernova progenitors. We also argue that an increase in reddening towards the end of the RSG phase, as observed for the two most evolved cluster stars, may provide a solution to the RSG problem.

  16. Dynamics of Kepler's supernova remnant

    NASA Technical Reports Server (NTRS)

    Borkowski, Kazimierz J.; Blondin, John M.; Sarazin, Craig L.

    1992-01-01

    Observations of Kepler's SNR have revealed a strong interaction with the ambient medium, far in excess of that expected at a distance of about 600 pc away from the Galactic plane where Kepler's SNR is located. This has been interpreted as a result of the interaction of supernova ejecta with the dense circumstellar medium (CSM). Based on the bow-shock model of Bandiera (1985), we study the dynamics of this interaction. The CSM distribution consists of an undisturbed stellar wind of a moving supernova progenitor and a dense shell formed in its interaction with a tenuous interstellar medium. Supernova ejecta drive a blast wave through the stellar wind which splits into the transmitted and reflected shocks upon hitting this bow-shock shell. We identify the transmitted shock with the nonradiative, Balmer-dominated shocks found recently in Kepler's SNR. The transmitted shock most probably penetrated the shell in the vicinity of the stagnation point.

  17. Featured Image: Modeling Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    This image shows a computer simulation of the hydrodynamics within a supernova remnant. The mixing between the outer layers (where color represents the log of density) is caused by turbulence from the Rayleigh-Taylor instability, an effect that arises when the expanding core gas of the supernova is accelerated into denser shell gas. The past standard for supernova-evolution simulations was to perform them in one dimension and then, in post-processing, manually smooth out regions that undergo Rayleigh-Taylor turbulence (an intrinsically multidimensional effect). But in a recent study, Paul Duffell (University of California, Berkeley) has explored how a 1D model could be used to reproduce the multidimensional dynamics that occur in turbulence from this instability. For more information, check out the paper below!CitationPaul C. Duffell 2016 ApJ 821 76. doi:10.3847/0004-637X/821/2/76

  18. INFRARED OBSERVATIONAL MANIFESTATIONS OF YOUNG DUSTY SUPER STAR CLUSTERS

    SciTech Connect

    Martínez-González, Sergio; Tenorio-Tagle, Guillermo; Silich, Sergiy

    2016-01-01

    The growing evidence pointing at core-collapse supernovae as large dust producers makes young massive stellar clusters ideal laboratories to study the evolution of dust immersed in a hot plasma. Here we address the stochastic injection of dust by supernovae, and follow its evolution due to thermal sputtering within the hot and dense plasma generated by young stellar clusters. Under these considerations, dust grains are heated by means of random collisions with gas particles which result in the appearance of  infrared spectral signatures. We present time-dependent infrared spectral energy distributions that are to be expected from young stellar clusters. Our results are based on hydrodynamic calculations that account for the stochastic injection of dust by supernovae. These also consider gas and dust radiative cooling, stochastic dust temperature fluctuations, the exit of dust grains out of the cluster volume due to the cluster wind, and a time-dependent grain size distribution.

  19. The ASTRODEEP Frontier Fields catalogues. II. Photometric redshifts and rest frame properties in Abell-2744 and MACS-J0416

    NASA Astrophysics Data System (ADS)

    Castellano, M.; Amorín, R.; Merlin, E.; Fontana, A.; McLure, R. J.; Mármol-Queraltó, E.; Mortlock, A.; Parsa, S.; Dunlop, J. S.; Elbaz, D.; Balestra, I.; Boucaud, A.; Bourne, N.; Boutsia, K.; Brammer, G.; Bruce, V. A.; Buitrago, F.; Capak, P.; Cappelluti, N.; Ciesla, L.; Comastri, A.; Cullen, F.; Derriere, S.; Faber, S. M.; Giallongo, E.; Grazian, A.; Grillo, C.; Mercurio, A.; Michałowski, M. J.; Nonino, M.; Paris, D.; Pentericci, L.; Pilo, S.; Rosati, P.; Santini, P.; Schreiber, C.; Shu, X.; Wang, T.

    2016-05-01

    Aims: We present the first public release of photometric redshifts, galaxy rest frame properties and associated magnification values in the cluster and parallel pointings of the first two Frontier Fields, Abell-2744 and MACS-J0416. The released catalogues aim to provide a reference for future investigations of extragalactic populations in these legacy fields: from lensed high-redshift galaxies to cluster members themselves. Methods: We exploit a multiwavelength catalogue, ranging from Hubble Space Telescope (HST) to ground-based K and Spitzer IRAC, which is specifically designed to enable detection and measurement of accurate fluxes in crowded cluster regions. The multiband information is used to derive photometric redshifts and physical properties of sources detected either in the H-band image alone, or from a stack of four WFC3 bands. To minimize systematics, median photometric redshifts are assembled from six different approaches to photo-z estimates. Their reliability is assessed through a comparison with available spectroscopic samples. State-of-the-art lensing models are used to derive magnification values on an object-by-object basis by taking into account sources positions and redshifts. Results: We show that photometric redshifts reach a remarkable ~3-5% accuracy. After accounting for magnification, the H-band number counts are found to be in agreement at bright magnitudes with number counts from the CANDELS fields, while extending the presently available samples to galaxies that, intrinsically, are as faint as H ~ 32-33, thanks to strong gravitational lensing. The Frontier Fields allow the galaxy stellar mass distribution to be probed, depending on magnification, at 0.5-1.5 dex lower masses with respect to extragalactic wide fields, including sources at Mstar ~ 107-108 M⊙ at z > 5. Similarly, they allow the detection of objects with intrinsic star formation rates (SFRs) >1 dex lower than in the CANDELS fields reaching 0.1-1 M⊙/yr at z ~ 6-10. The

  20. A bright z = 5.2 lensed submillimeter galaxy in the field of Abell 773. HLSJ091828.6+514223

    NASA Astrophysics Data System (ADS)

    Combes, F.; Rex, M.; Rawle, T. D.; Egami, E.; Boone, F.; Smail, I.; Richard, J.; Ivison, R. J.; Gurwell, M.; Casey, C. M.; Omont, A.; Berciano Alba, A.; Dessauges-Zavadsky, M.; Edge, A. C.; Fazio, G. G.; Kneib, J.-P.; Okabe, N.; Pelló, R.; Pérez-González, P. G.; Schaerer, D.; Smith, G. P.; Swinbank, A. M.; van der Werf, P.

    2012-02-01

    During our Herschel Lensing Survey (HLS) of massive galaxy clusters, we have discovered an exceptionally bright source behind the z = 0.22 cluster Abell 773, which appears to be a strongly lensed submillimeter galaxy (SMG) at z = 5.2429. This source is unusual compared to most other lensed sources discovered by Herschel so far, because of its higher submm flux (~200 mJy at 500 μm) and its high redshift. The dominant lens is a foreground z = 0.63 galaxy, not the cluster itself. The source has a far-infrared (FIR) luminosity of LFIR = 1.1 × 1014/μ L⊙, where μ is the magnification factor, likely ~11. We report here the redshift identification through CO lines with the IRAM-30 m, and the analysis of the gas excitation, based on CO(7-6), CO(6-5), CO(5-4) detected at IRAM and the CO(2-1) at the EVLA. All lines decompose into a wide and strong red component, and a narrower and weaker blue component, 540 km s-1 apart. Assuming the ultraluminous galaxy (ULIRG) CO-to-H2 conversion ratio, the H2 mass is 5.8 × 1011/μ M⊙, of which one third is in a cool component. From the C I(3P2-3P1) line we derive a C I/H2 number abundance of 6 × 10-5 similar to that in other ULIRGs. The H2Op(2,0,2-1,1,1) line is strong only in the red velocity component, with an intensity ratio I(H2O)/I(CO) ~ 0.5, suggesting a strong local FIR radiation field, possibly from an active nucleus (AGN) component. We detect the [NII]205 μm line for the first time at high-z. It shows comparable blue and red components, with a strikingly broad blue one, suggesting strong ionized gas flows.

  1. Software Based Supernova Recognition

    NASA Astrophysics Data System (ADS)

    Walters, Stephen M.

    2014-05-01

    This paper describes software for detecting Supernova (SN) in images. The software can operate in real-time to discover SN while data is being collected so the instrumentation can immediately be re-tasked to perform spectroscopy or photometry of a discovery. Because the instrumentation captures two images per minute, the realtime budget is constrained to 30 seconds per target, a challenging goal. Using a set of two to four images, the program creates a "Reference" (REF) image and a "New" (NEW) image where all images are used in both NEW and REF but any SN survives the combination process only in the NEW image. This process produces good quality images having similar noise characteristics but without artifacts that might be interpreted as SN. The images are then adjusted for seeing and brightness differences using a variant of Tomaney and Crotts method of Point Spread Function (PSF) matching after which REF is subtracted from NEW to produce a Difference (DIF) image. A Classifier is then trained on a grid of artificial SN to estimate the statistical properties of four attributes and used in a process to mask false positives that can be clearly identified as such. Further training to avoid any remaining false positives sets the range, in standard deviations for each attribute, that the Classifier will accept as a valid SN. This training enables the Classifier to discriminate between SN and most subtraction residue. Lastly, the DIF image is scanned and measured by the Classifier to find locations where all four properties fall within their acceptance ranges. If multiple locations are found, the one best conforming to the training estimates is chosen. This location is then declared as a Candidate SN, the instrumentation re-tasked and the operator notified.

  2. Dust around Type Ia supernovae

    SciTech Connect

    Wang, Lifan

    2005-10-20

    An explanation is given of the low value of R lambda triple bond A lambda/E(B - V), the ratio of absolute to selective extinction deduced from Type Ia supernova observations. The idea involves scattering by dust clouds located in the circumstellar environment, or at the highest velocity shells of the supernova ejecta. The scattered light tends to reduce the effective R lambda in the optical, but has an opposite effect in the ultraviolet. The presence of circumstellar dust can be tested by ultraviolet to near infrared observations and by multi-epoch spectropolarimetry of SNe Ia.

  3. Educational Resources on Supernovae for Children

    NASA Astrophysics Data System (ADS)

    Struck, James T.

    The National Science Education Standards (1996, National Academy Press) suggest mention of objects like the ``sun, moon, stars" in grades K-4 and element formation in grades 9-12. Children's librarians and some astronomy librarians should know about some of the resources for children on supernovae not only because supernovae are critical to higher element formation, but also to educate others about the universe's expansion and stars. In addition, basic bibliometrics on these resources yields lessons on the importance of using many indexes, the pattern of literature for children on supernovae, the types of resources on supernovae, and the scattering of resources/information for children on supernovae.

  4. VLA Discovers Giant Rings Around Galaxy Cluster

    NASA Astrophysics Data System (ADS)

    2006-11-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope have discovered giant, ring-like structures around a cluster of galaxies. The discovery provides tantalizing new information about how such galaxy clusters are assembled, about magnetic fields in the vast spaces between galaxy clusters, and possibly about the origin of cosmic rays. Radio-Optical Image of Cluster Galaxy Cluster Abell 3376 (Radio/Optical) CREDIT: Joydeep Bagchi, IUCAA, NRAO/AUI/NSF Above, a combined radio/optical image shows the galaxy cluster Abell 3376 in visible light (blue) and radio (red) images. The giant radio arcs surrounding the cluster were discovered using the Very Large Array. The visible-light image is from the Digitized Sky survey. Below, an X-ray image of Abell 3376 made using the European Space Agency's XMM-Newton telescope shows a spectacular, bullet-shaped region of X-rays coming from gas heated to 60 million degrees Kelvin. The bullet shape results from the supersonic collision of a smaller smaller galaxy subcluster with the main body of the larger cluster. Click on images for larger version. X-Ray Image of Cluster Galaxy Cluster Abell 3376 (X-Ray) CREDIT: Joydeep Bagchi, IUCAA, ESA "These giant, radio-emitting rings probably are the result of shock waves caused by violent collisions of smaller groups of galaxies within the cluster," said Joydeep Bagchi, of the Inter-University Centre for Astronomy and Astrophysics in Pune, India, who led an international research team. The scientists reported their findings in the November 3 edition of the journal Science. The newly-discovered ring segments, some 6 million light-years across, surround a galaxy cluster called Abell 3376, more than 600 million light-years from Earth. They were revealed because fast-moving electrons emitted radio waves as they spiraled around magnetic field lines in intergalactic space. "Even from this large distance, the feeble radio waves were easily picked up by the VLA

  5. Magnetar-Powered Supernovae in Two Dimensions. I. Superluminous Supernovae

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung; Woosley, S. E.; Sukhbold, Tuguldur

    2016-11-01

    Previous studies have shown that the radiation emitted by a rapidly rotating magnetar embedded in a young supernova can greatly amplify its luminosity. These one-dimensional studies have also revealed the existence of an instability arising from the piling up of radiatively accelerated matter in a thin dense shell deep inside the supernova. Here, we examine the problem in two dimensions and find that, while instabilities cause mixing and fracture this shell into filamentary structures that reduce the density contrast, the concentration of matter in a hollow shell persists. The extent of the mixing depends upon the relative energy input by the magnetar and the kinetic energy of the inner ejecta. The light curve and spectrum of the resulting supernova will be appreciably altered, as will the appearance of the supernova remnant, which will be shellular and filamentary. A similar pile up and mixing might characterize other events where energy is input over an extended period by a centrally concentrated source, e.g., a pulsar, radioactive decay, a neutrino-powered wind, or colliding shells. The relevance of our models to the recent luminous transient ASASSN-15lh is briefly discussed.

  6. Role of clusters in nuclear astrophysics with Cluster Nucleosynthesis Diagram (CND)

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, H.; Kahl, D.; Yamaguchi, H.; Wakabayashi, Y.; Teranishi, T.; Iwasa, N.; Komatsubara, T.; Kato, S.; Chen, A.; Cherubini, S.; Choi, S. H.; Hahn, I. S.; He, J. J.; Khiem, Le Hong; Lee, C. S.; Kwon, Y. K.; Wanajo, S.; Janka, H.-T.

    2013-04-01

    The role of nuclear clustering in stellar reactions is discussed, with Cluster Nucleosynthesis Diagram (CND) proposed before, for nucleosynthesis in stellar evolution and explosive stellar phenomena. Special emphasis is placed on α-induced stellar reactions. We report here the first experimental evidence that a cluster resonances dominate the (α,p) stellar reaction cross sections that is crucial for the vp-process in core-collapse supernovae.

  7. Are supernovae recorded in indigenous astronomical traditions?

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.

    2014-07-01

    Novae and supernovae are rare astronomical events that would have had an influence on the skywatching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in indigenous oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral traditions and material culture, and claims from around the world are discussed to determine if they meet these criteria. Aboriginal Australian traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Aboriginal traditions, there are currently no confirmed accounts of supernovae in Indigenous Australian oral or material traditions.

  8. MHD simulations of supernova driven ISM turbulence

    NASA Astrophysics Data System (ADS)

    Gressel, Oliver; Ziegler, Udo

    The dynamic evolution of the (stratified) turbulent interstellar medium (ISM) is simulated utilizing a three-dimensional MHD model including various physical effects. The computational domain covers a box of 0.5x0.5x2.0 kpc at a resolution of typically 128x128x1024 grid cells. The model includes (constant kinematic) viscosity and magnetic diffusivity. The adiabatic equation of state is supplemented by a parameterized heating- and cooling-function allowing for thermal instability (TI). The update due to heating and cooling is implemented implicitly using a Patankar-type discretization. Turbulence is driven by supernova explosions which are modelled as local injections of thermal energy, smeared over three standard-deviations of a Gaussian support with FWHM of 20pc. Supernova rates are adopted for typical cited values. Within our model we make a distinction between Type I and Type II SNe. Latter are statistically clustered by the (artificial) constraint that the density at the explosion site be above average (with respect to a horizontal slab) - former are spatially uncorrelated. The dual-energy feature of the conservative NIRVANA-code is used to tackle the extreme ratio of kinetic to internal energy that arises from the violent energy input. We stress the importance of using a conservative scheme to properly transfer the injected energy to kinetic motion. The model also includes a differentially rotating background (with shearing boundary conditions in radial direction) as well as vertical stratification. The initial density and pressure profiles are in hydrostatic equilibrium with respect to the equation of state given by the radiative equilibrium. Including z-dependent heating rates this leads to a considerable deviation from usual isothermal initial models. The primary focus of this work is on the galactic dynamo and the generation of large-scale magnetic fields. As a secondary target we are also interested in general properties of the ISM that are of importance

  9. The supernova: A stellar spectacle

    NASA Technical Reports Server (NTRS)

    Straka, W. C.

    1976-01-01

    The life of a star, the supernova, related objects and their importance in astronomy and science in general are discussed. Written primarily for science teachers of secondary school chemistry, physics, and earth sciences, the booklet contains a glossary, reference sources, suggested topics for discussion, and projects for individual or group assignment.

  10. Nonstandard neutrino interactions in supernovae

    NASA Astrophysics Data System (ADS)

    Stapleford, Charles J.; Väänänen, Daavid J.; Kneller, James P.; McLaughlin, Gail C.; Shapiro, Brandon T.

    2016-11-01

    Nonstandard interactions (NSI) of neutrinos with matter can significantly alter neutrino flavor evolution in supernovae with the potential to impact explosion dynamics, nucleosynthesis, and the neutrinos signal. In this paper, we explore, both numerically and analytically, the landscape of neutrino flavor transformation effects in supernovae due to NSI and find a new, heretofore unseen transformation processes can occur. These new transformations can take place with NSI strengths well below current experimental limits. Within a broad swath of NSI parameter space, we observe symmetric and standard matter-neutrino resonances for supernovae neutrinos, a transformation effect previously only seen in compact object merger scenarios; in another region of the parameter space we find the NSI can induce neutrino collective effects in scenarios where none would appear with only the standard case of neutrino oscillation physics; and in a third region the NSI can lead to the disappearance of the high density Mikheyev-Smirnov-Wolfenstein resonance. Using a variety of analytical tools, we are able to describe quantitatively the numerical results allowing us to partition the NSI parameter according to the transformation processes observed. Our results indicate nonstandard interactions of supernova neutrinos provide a sensitive probe of beyond the Standard Model physics complementary to present and future terrestrial experiments.

  11. The Supernova - A Stellar Spectacle.

    ERIC Educational Resources Information Center

    Straka, W. C.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The following topics concerning supernovae are included: the outburst as observed and according to theory, the stellar remnant, the nebular remnant, and a summary…

  12. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Shibagaki, S.; Mathews, G. J.; Nakamura, K.; Suzuki, T.

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  13. Radio studies of extragalactic supernovae.

    PubMed

    Weiler, K W; Sramek, R A; Panagia, N

    1986-03-14

    Some exploding stars (supernovae) are powerful emitters of centimeter radio radiation. Detailed observations have shown that these supernovae quickly become detectable in the radio range, first at shorter wavelengths (higher frequencies) and later at progressively longer and longer wavelengths (lower frequencies). This part of the phenomenon appears to be well explained by a monotonic decrease in the amount of ionized material surrounding the radio-emitting regions as the shock from the explosion travels outward. The radio emission itself is of a nonthermal, synchrotron origin, as is the case in most bright cosmic radio sources. Once the absorption effects become negligible, the radio intensity declines with time until reaching the detection limit of the telescope. Models suggest that the absorbing material originates in a dense wind of matter lost by the supernova progenitor star, or by its companion if it is in a binary system, in the last stages of evolution before the explosion. The synchrotron radio emission can be generated either externally by the shock wave from the explosion propagating through this same high density stellar wind or internally by a rapidly rotating neutron star, which is the collapsed core of the exploded star. Present results appear to favor the former model for at least the first several years after the supernova explosion, although the latter model remains viable.

  14. Cosmology from High Redshift Supernovae

    NASA Astrophysics Data System (ADS)

    Garnavich, Peter

    The discovery of a correlation between the light curve shape and intrinsic b rightness has made Type Ia supernovae exceptionally accurate distance indicators out to cosmologically interesting redshifts. Ground-based searches and follow-up as well as Hubble S pace Telescope observations of Type Ia supernovae have produced a significant number of object s with redshifts between 0.3 and 1.0. The distant SNe, when combined with a local samp le analyzed in the same way, provide reliable constraints on the deceleration and age of th e Universe. Early this year, an analysis of a handful of Type Ia events indicated that the deceleration was too small for gravitating matter alone to make a flat Universe. A larger sa mple of supernovae gives the surprising result that the Universe is accelerating, implying the exi stence of a cosmological constant or some other exotic form of energy. The success of this research has depended on the development of algorithms and software to register, scale and subtract CCD images taken weeks apart and to search for var iable objects. A good fraction of the point-sources identified are asteroids, variable stars, or AGN, so spectra are needed to confirm the identification as a Type Ia supernova and obt ain a redshift. The best candidates are followed photometrically to construct light curves. The steps to transform the observed light curves into cosmologically interestin g results will also be described.

  15. Pulsational Pair-instability Supernovae

    NASA Astrophysics Data System (ADS)

    Woosley, S. E.

    2017-02-01

    The final evolution of stars in the mass range 70–140 {\\text{}}{M}ȯ is explored. Depending upon their mass loss history and rotation rates, these stars will end their lives as pulsational pair-instability supernovae (PPISN) producing a great variety of observational transients with total durations ranging from weeks to millennia and luminosities from 1041 to over 1044 erg s‑1. No nonrotating model radiates more than 5× {10}50 erg of light or has a kinetic energy exceeding 5× {10}51 erg, but greater energies are possible, in principle, in magnetar-powered explosions, which are explored. Many events resemble SNe Ibn, SNe Icn, and SNe IIn, and some potential observational counterparts are mentioned. Some PPISN can exist in a dormant state for extended periods, producing explosions millennia after their first violent pulse. These dormant supernovae contain bright Wolf–Rayet stars, possibly embedded in bright X-ray and radio sources. The relevance of PPISN to supernova impostors like Eta Carinae, to superluminous supernovae, and to sources of gravitational radiation is discussed. No black holes between 52 and 133 {\\text{}}{M}ȯ are expected from stellar evolution in close binaries.

  16. The High-Mass End of the Black Hole Mass Function: Mass Estimates in Brightest Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Dalla Bontà, E.; Ferrarese, L.; Corsini, E. M.; Miralda-Escudé, J.; Coccato, L.; Sarzi, M.; Pizzella, A.; Beifiori, A.

    2009-01-01

    We present Hubble Space Telescope imaging and spectroscopic observations of three Brightest Cluster Galaxies, Abell 1836-BCG, Abell 2052-BCG, and Abell 3565-BCG, obtained with the Wide Field and Planetary Camera 2, the Advanced Camera for Surveys and the Space Telescope Imaging Spectrograph. The data provide detailed information on the structure and mass profile of the stellar component, the dust optical depth, and the spatial distribution and kinematics of the ionized gas within the innermost region of each galaxy. Dynamical models, which account for the observed stellar mass profile and include the contribution of a central supermassive black hole (SBH), are constructed to reproduce the kinematics derived from the Hα and [N II]λλ6548,6583 emission lines. Secure SBH detection with M • = 3.61+0.41 -0.50 × 109 M sun and M • = 1.34+0.21 -0.19 × 109 M sun, respectively, are obtained for Abell 1836-BCG and Abell 3565-BCG, which show regular rotation curves and strong central velocity gradients. In the case of Abell 2052-BCG, the lack of an orderly rotational motion prevents a secure determination, although an upper limit of M • lsim 4.60 × 109 M sun can be placed on the mass of the central SBH. These measurements represent an important step forward in the characterization of the high-mass end of the SBH mass function. Based on observations made with ESO telescopes at the La Silla Paranal Observatory under programme ID 279.B-5004(A).

  17. Core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Mueller, Bernhard

    2017-01-01

    Core-collapse supernovae, the deaths of massive stars, are among the most spectacular phenomena in astrophysics: Not only can supernovae outshine their host galaxy for weeks; they are also laboratories for the behavior of matter at supranuclear densities, and one of the few environments where collective neutrino effects can become important. Moreover, supernovae play a central role in the cosmic matter cycle, e.g., as the dominant producers of oxygen in the Universe. Yet the mechanism by which massive stars explode has eluded us for decades, partly because classical astronomical observations across the electromagnetic spectrum cannot directly probe the supernovae ``engine''. Numerical simulations are thus our primary tool for understanding the explosion mechanism(s) of massive stars. Rigorous modeling needs to take a host of important physical ingredients into account, such as the emission and partial reabsorption of neutrinos from the young proto-neutron star, multi-dimensional fluid motions, general relativistic gravity, the equation of state of nuclear matter, and magnetic fields. This is a challenging multi-physics problem that has not been fully solved yet. Nonetheless, as I shall argue in this talk, recent first-principle 3D simulations have gone a long way towards demonstrating the viability of the most popular explosion scenario, the ``neutrino-driven mechanism''. Focusing on successful explosion models of the MPA-QUB-Monash collaboration, I will discuss possible requirements for robust explosions across a wide range of progenitors, such as accurate neutrino opacities, stellar rotation, and seed asymmetries from convective shell burning. With the advent of successful explosion models, supernova theory can also be confronted with astronomical observations. I will show that recent 3D models come closer to matching observed explosion parameters (explosion energies, neutron star kicks) than older 2D models, although there are still discrepancies. This work has

  18. Luminosity segregation in three clusters of galaxies (A119, A2443, A2218)

    NASA Astrophysics Data System (ADS)

    Pracy, Michael B.; Driver, Simon P.; De Propris, Roberto; Couch, Warrick J.; Nulsen, Paul E. J.

    2005-12-01

    We use deep wide-field V-band imaging obtained with the Wide Field Camera at the prime focus of the Issac Newton Telescope to study the spatial and luminosity distribution of galaxies in three low redshift (0.04 < z < 0.2) clusters: Abell 119, Abell 2443 and Abell 2218. The absolute magnitude limits probed in these clusters are MV- 5 logh0.7=-13.3, -15.4 and -16.7mag, respectively. The galaxy population, at all luminosities, along the line-of-sight to the clusters can be described by the linear combination of a King profile and a constant surface density of field galaxies. We find that, for these three clusters, the core radius is invariant with intrinsic luminosity of the cluster population to the above limits and thus there is no evidence for luminosity segregation in these clusters. The exception is the brightest galaxies in A2218 which exhibit a more compact spatial distribution. We find that the total projected luminosity distribution (within 1h-10.7Mpc of the cluster centre) can be well represented by a single Schechter function with moderately flat faint-end slopes: α=-1.22+0.07-0.06 (A119), α=-1.11+0.10-0.09 (A2443) and α=-1.14+0.08-0.07 (A2218). We perform a geometric deprojection of the cluster galaxy population and confirm that no `statistically significant' evidence of a change in the shape of the luminosity distribution with cluster-centric radius exists. Again, the exception being A2218 which exhibits a core region with a flatter faint-end slope.

  19. How multiple supernovae overlap to form superbubbles

    NASA Astrophysics Data System (ADS)

    Yadav, Naveen; Mukherjee, Dipanjan; Sharma, Prateek; Nath, Biman B.

    2017-02-01

    We explore the formation of superbubbles through energy deposition by multiple supernovae (SNe) in a uniform medium. We use the total energy conserving, 3D hydrodynamic simulations to study how SNe correlated in space and time create superbubbles. While isolated SNe fizzle out completely by ∼1 Myr due to radiative losses, for a realistic cluster size it is likely that subsequent SNe go off within the hot/dilute bubble and sustain the shock till the cluster lifetime. For realistic cluster sizes, we find that the bubble remains overpressured only if, for a given ng0, NOB is sufficiently large. While most of the input energy is still lost radiatively, superbubbles can retain up to ∼5-10 per cent of the input energy in the form of kinetic+thermal energy till 10 Myr for interstellar medium density ng0 ≈ 1 cm-3. We find that the mechanical efficiency decreases for higher densities (η _mech ∝ n_{g0}^{-2/3}). We compare the radii and velocities of simulated supershells with observations and the classical adiabatic model. Our simulations show that the superbubbles retain only ≲ 10 per cent of the injected energy, thereby explaining the observed smaller size and slower expansion of supershells. We also confirm that a sufficiently large (≳ 104) number of SNe are required to go off in order to create a steady wind with a stable termination shock within the superbubble. We show that the mechanical efficiency increases with increasing resolution, and that explicit diffusion is required to obtain converged results.

  20. The SILCC project - III. Regulation of star formation and outflows by stellar winds and supernovae

    NASA Astrophysics Data System (ADS)

    Gatto, Andrea; Walch, Stefanie; Naab, Thorsten; Girichidis, Philipp; Wünsch, Richard; Glover, Simon C. O.; Klessen, Ralf S.; Clark, Paul C.; Peters, Thomas; Derigs, Dominik; Baczynski, Christian; Puls, Joachim

    2017-04-01

    We study the impact of stellar winds and supernovae on the multiphase interstellar medium using three-dimensional hydrodynamical simulations carried out with FLASH. The selected galactic disc region has a size of (500 pc)2 × ±5 kpc and a gas surface density of 10 M⊙ pc-2. The simulations include an external stellar potential and gas self-gravity, radiative cooling and diffuse heating, sink particles representing star clusters, stellar winds from these clusters that combine the winds from individual massive stars by following their evolution tracks, and subsequent supernova explosions. Dust and gas (self-) shielding is followed to compute the chemical state of the gas with a chemical network. We find that stellar winds can regulate star (cluster) formation. Since the winds suppress the accretion of fresh gas soon after the cluster has formed, they lead to clusters that have lower average masses (102-104.3 M⊙) and form on shorter time-scales (10-3-10 Myr). In particular, we find an anticorrelation of cluster mass and accretion time-scale. Without winds, the star clusters easily grow to larger masses for ∼5 Myr until the first supernova explodes. Overall, the most massive stars provide the most wind energy input, while objects beginning their evolution as B-type stars contribute most of the supernova energy input. A significant outflow from the disc (mass loading ≳1 at 1 kpc) can be launched by thermal gas pressure if more than 50 per cent of the volume near the disc mid-plane can be heated to T > 3 × 105 K. Stellar winds alone cannot create a hot volume-filling phase. The models that are in best agreement with observed star formation rates drive either no outflows or weak outflows.

  1. First measurement of σ8 using supernova magnitudes only

    NASA Astrophysics Data System (ADS)

    Castro, Tiago; Quartin, Miguel

    2014-09-01

    A method was recently proposed which allows the conversion of the weak-lensing effects in the Type Ia supernova (SNeIa) Hubble diagram from noise into signal. Such signal is sensitive to the growth of structure in the universe, and in particular can be used as a measurement of σ8 independently from more traditional methods such as those based on the cosmic microwave background, cosmic shear or cluster abundance. We extend here that analysis to allow for intrinsic non-Gaussianities in the supernova probability distribution function, and discuss how this can be best modelled using the Bayes factor. Although it was shown that a precise measurement of σ8 requires ˜105 SNeIa, current data already allow an important proof of principle. In particular, we make use of the 706 supernovae with z ≤ 0.9 of the recent Joint Lightcurve Analysis catalogue and show that a simple treatment of intrinsic non-Gaussianities with a couple of nuisance parameters is enough for our method to yield the values σ _8 = 0.84^{+0.28}_{-0.65} or σ8 < 1.45 at a 2σ confidence level. This result is consistent with mock simulations and it is also in agreement with independent measurements and presents the first ever measurement of σ8 using SNeIa magnitudes alone.

  2. Detecting galaxy clusters in the DLS and CARS: a Bayesian cluster finder

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Wittman, D.; Benítez, N.

    2011-11-01

    The detection of galaxy clusters in present and future surveys enables measuring mass-to-light ratios, clustering properties or galaxy cluster abundances and therefore, constraining cosmological parameters. We present a new technique for detecting galaxy clusters, which is based on the Matched Filter Algorithm from a Bayesian point of view. The method is able to determine the position, redshift and richness of the cluster through the maximization of a filter depending on galaxy luminosity, density and photometric redshift combined with a galaxy cluster prior. We tested the algorithm through realistic mock galaxy catalogs, revealing that the detections are 100% complete and 80% pure for clusters up to z < 1.2 and richer than λ ≥ 25 (Abell richness ≥ 0). We applied the algorithm to the CFHTLS Archive Research Survey (CARS) data, recovering similar detections as previously published using the same data plus additional clusters that are very probably real. We also applied this algorithm to the Deep Lens Survey (DLS), obtaining the first sample of optical-selected galaxy in this survey. The sample is complete up to redshift 0.7 and we detect more than 780 cluster candidates up to redshift 1.2. We conclude by discussing the differences between previous weak lensing detections in this survey and optical detections in both samples.

  3. The Butcher-Oemler effect in a nearby cluster of galaxies

    SciTech Connect

    Vigroux, L.; Boulade, O.; Rose, J.A. North Carolina Univ., Chapel Hill )

    1989-12-01

    The integrated spectra of early-type galaxies in the nearby Abell 262, Pegasus I, and Virgo clusters are compared with those of several field galaxies. The spectra of five galaxies in Pegasus I and one galaxy in the Virgo Cluster show evidence of recent star formation. The average blue magnitude for the star-forming galaxies is M(B) = -20. The star-formation activity in Pegasus I is found to be similar to that of starburst and poststarburst galaxies in Butcher-Oemler clusters at redshifts greater than 2. 38 refs.

  4. Compton Observatory observations of clusters of galaxies and extragalactic radio sources

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This task involved the investigation of the emission of clusters of galaxies, particularly those which contain extended radio emission, in the gamma-ray region of the spectrum. Observations were made of several clusters using the Compton Observatory EGRET instrument. For each cluster a measured flux or upper limit on the gamma-ray flux was obtained. In only one case, Abell 2199, was there a significant measured flux. This source is spatially confused with a know blazar in the field of view. The observation is consistent with all emissions being from the blazar.

  5. Inverting ion images without Abel inversion: maximum entropy reconstruction of velocity maps.

    PubMed

    Dick, Bernhard

    2014-01-14

    A new method for the reconstruction of velocity maps from ion images is presented, which is based on the maximum entropy concept. In contrast to other methods used for Abel inversion the new method never applies an inversion or smoothing to the data. Instead, it iteratively finds the map which is the most likely cause for the observed data, using the correct likelihood criterion for data sampled from a Poissonian distribution. The entropy criterion minimizes the information content in this map, which hence contains no information for which there is no evidence in the data. Two implementations are proposed, and their performance is demonstrated with simulated and experimental data: Maximum Entropy Velocity Image Reconstruction (MEVIR) obtains a two-dimensional slice through the velocity distribution and can be compared directly to Abel inversion. Maximum Entropy Velocity Legendre Reconstruction (MEVELER) finds one-dimensional distribution functions Q(l)(v) in an expansion of the velocity distribution in Legendre polynomials P((cos θ) for the angular dependence. Both MEVIR and MEVELER can be used for the analysis of ion images with intensities as low as 0.01 counts per pixel, with MEVELER performing significantly better than MEVIR for images with low intensity. Both methods perform better than pBASEX, in particular for images with less than one average count per pixel.

  6. Finding Distances to Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    Type Ia supernovae are known as standard candles due to their consistency, allowing us to measure distances based on their brightness. But what if these explosions arent quite as consistent as we thought? Due scientific diligence requires careful checks, so a recent study investigates whether the metallicity of a supernovas environment affects the peak luminosity of the explosion.Metallicity Dependence?Type Ia supernovae are incredibly powerful tools for determining distances in our universe. Because these supernovae are formed by white dwarfs that explode when they reach a uniform accreted mass, the supernova peak luminosity is thought to be very consistent. This consistency allows these supernovae to be used as standard candles to measure distances to their host galaxies.But what if that peak luminosity is affected by a factor that we havent taken into account? Theorists have proposed that the luminosities of Type Ia supernovae might depend on the metallicity of their environments with high-metallicity environments suppressing supernova luminosities. If this is true, then we could be systematically mis-measuring cosmological distances using these supernovae.Testing AbundancesSupernova brightnesses vs. the metallicity of their environments. Low-metallicity supernovae (blue shading) and high-metallicity supernovae (red shading) have an average magnitude difference of ~0.14. [Adapted from Moreno-Raya et al. 2016]A team led by Manuel Moreno-Raya, of the Center for Energy, Environment and Technology (CIEMAT) in Spain, has observed 28 Type Ia supernovae in an effort to test for such a metallicity dependence. These supernovae each have independent distance measurements (e.g., from Cepheids or the Tully-Fisher relation).Moreno-Raya and collaborators used spectra from the 4.2-m William Herschel Telescope to estimate oxygen abundances in the region where each of these supernovae exploded. They then used these measurements to determine if metallicity of the local region

  7. Gravitational lensing statistics of amplified supernovae

    NASA Technical Reports Server (NTRS)

    Linder, Eric V.; Wagoner, Robert V.; Schneider, P.

    1988-01-01

    Amplification statistics of gravitationally lensed supernovae can provide a valuable probe of the lensing matter in the universe. A general probability distribution for amplification by compact objects is derived which allows calculation of the lensed fraction of supernovae at or greater than an amplification A and at or less than an apparent magnitude. Comparison of the computed fractions with future results from ongoing supernova searches can lead to determination of the mass density of compact dark matter components with masses greater than about 0.001 solar mass, while the time-dependent amplification (and polarization) of the expanding supernovae constrain the individual masses. Type II supernovae are found to give the largest fraction for deep surveys, and the optimum flux-limited search is found to be at approximately 23d magnitude, if evolution of the supernova rate is neglected.

  8. La supernova galattica è in ritardo?

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2005-06-01

    After 400 years we are still waiting to see a galactic supernova. A simple galactic model based upon interstellar absorption is shown in order to explain the rate of observed galactic supernovae. The history of variable stars observations in modern epoch is sketched and the hypothesis for Bethlehem Star made by Kepler in occasion of the last galactic supernova, exploded in Ophiuchus on 9 October 1604, is also presented.

  9. Magnetares como fuentes para potenciar supernovas superluminosas

    NASA Astrophysics Data System (ADS)

    Bersten, M. C.; Benvenuto, O. G.

    2016-08-01

    Magnetars have been proposed as one of the possible sources to power the light curve of super-luminous supernovae. We have included the energy deposited by a hypothetical magnetar in our one-dimensional hydrodynamical code, and analyzed the dynamical effect on the supernova ejecta. In particular, we present a model for SN 2011kl, the first object associated with a ultra-long-duration gamma-ray burst. Finally, we show its effect on the light curves of hydrogen rich supernovae.

  10. Connecting supernovae with their environments

    NASA Astrophysics Data System (ADS)

    Galbany, L.

    2017-03-01

    We present MUSE observations of galaxy NGC 7469 from its Science Verification to show how powerful is the combination of high-resolution wide-field integral field spectroscopy with both photometric and spectroscopic observations of supernova (SN) explosions. Using STARLIGHT and H II explorer, we selected all H II regions of the galaxy and produced 2-dimensional maps of the Hα equivalent width, average luminosity-weighted stellar age, and oxygen abundance. We measured deprojected galactocentric distances for all H II regions, and radial gradients for all above-mentioned parameters. We positioned the type Ia SN2008ec in the Branch et al. diagram, and finally discussed the characteristics of the SN parent H II region compared to all other H II regions in the galaxy. In a near future, the AMUSING survey will be able to reproduce this analysis and construct statistical samples to enable the characterization of the progenitors of different supernova types.

  11. SUPERNOVA FALLBACK ONTO MAGNETARS AND PROPELLER-POWERED SUPERNOVAE

    SciTech Connect

    Piro, Anthony L.; Ott, Christian D. E-mail: cott@tapir.caltech.edu

    2011-08-01

    We explore fallback accretion onto newly born magnetars during the supernova of massive stars. Strong magnetic fields ({approx}10{sup 15} G) and short spin periods ({approx}1-10 ms) have an important influence on how the magnetar interacts with the infalling material. At long spin periods, weak magnetic fields, and high accretion rates, sufficient material is accreted to form a black hole, as is commonly found for massive progenitor stars. When B {approx}< 5 x 10{sup 14} G, accretion causes the magnetar to spin sufficiently rapidly to deform triaxially and produces gravitational waves, but only for {approx}50-200 s until it collapses to a black hole. Conversely, at short spin periods, strong magnetic fields, and low accretion rates, the magnetar is in the 'propeller regime' and avoids becoming a black hole by expelling incoming material. This process spins down the magnetar, so that gravitational waves are only expected if the initial protoneutron star is spinning rapidly. Even when the magnetar survives, it accretes at least {approx}0.3 M{sub sun}, so we expect magnetars born within these types of environments to be more massive than the 1.4 M{sub sun} typically associated with neutron stars. The propeller mechanism converts the {approx}10{sup 52} erg of spin energy in the magnetar into the kinetic energy of an outflow, which shock heats the outgoing supernova ejecta during the first {approx}10-30 s. For a small {approx}5 M{sub sun} hydrogen-poor envelope, this energy creates a brighter, faster evolving supernova with high ejecta velocities {approx}(1-3) x 10{sup 4} km s{sup -1} and may appear as a broad-lined Type Ib/c supernova. For a large {approx}> 10 M{sub sun} hydrogen-rich envelope, the result is a bright Type IIP supernova with a plateau luminosity of {approx}> 10{sup 43} erg s{sup -1} lasting for a timescale of {approx}60-80 days.

  12. Convection in Type 2 supernovae

    SciTech Connect

    Miller, Douglas Scott

    1993-10-15

    Results are presented here from several two dimensional numerical calculations of events in Type II supernovae. A new 2-D hydrodynamics and neutrino transport code has been used to compute the effect on the supernova explosion mechanism of convection between the neutrinosphere and the shock. This convection is referred to as exterior convection to distinguish it from convection beneath the neutrinosphere. The model equations and initial and boundary conditions are presented along with the simulation results. The 2-D code was used to compute an exterior convective velocity to compare with the convective model of the Mayle and Wilson 1-D code. Results are presented from several runs with varying sizes of initial perturbation, as well as a case with no initial perturbation but including the effects of rotation. The M&W code does not produce an explosion using the 2-D convective velocity. Exterior convection enhances the outward propagation of the shock, but not enough to ensure a successful explosion. Analytic estimates of the growth rate of the neutron finger instability axe presented. It is shown that this instability can occur beneath the neutrinosphere of the proto-neutron star in a supernova explosion with a growth time of ~ 3 microseconds. The behavior of the high entropy bubble that forms between the shock and the neutrinosphere in one dimensional calculations of supernova is investigated. It has been speculated that this bubble is a site for γ-process generation of heavy elements. Two dimensional calculations are presented of the time evolution of the hot bubble and the surrounding stellar material. Unlike one dimensional calculations, the 2D code fails to achieve high entropies in the bubble. When run in a spherically symmetric mode the 2-D code reaches entropies of ~ 200. When convection is allowed, the bubble reaches ~60 then the bubble begins to move upward into the cooler, denser material above it.

  13. Dust production in supernovae and AGB stars

    NASA Astrophysics Data System (ADS)

    Matsuura, Mikako

    2015-08-01

    In the last decade, the role of supernovae on dust has changed; it has been long proposed that supernovae are dust destroyers, but now recent observations show that core-collapse supernovae can become dust factories. Theoretical models of dust evolution in galaxies have predicted that core-collapse supernovae can be an important source of dust in galaxies, if these supernovae can form a significant mass of dust (0.1-1 solar masses). The Herschel Space Observatory and ALMA detected dust in the ejecta of Supernova 1987A. They revealed an estimated 0.5 solar masses of dust. Herschel also found nearly 0.1 solar masses of dust in historical supernovae remnants, namely Cassiopeia A and the Crab Nebula. If dust grains can survive future interaction with the supernova winds and ambient interstellar medium, core-collapse supernovae can be an important source of dust in the interstellar media of galaxies. We further discuss the total dust mass injected by AGB stars and SNe into the interstellar medium of the Magellanic Clouds.

  14. Cosmological constraints from strong gravitational lensing in clusters of galaxies.

    PubMed

    Jullo, Eric; Natarajan, Priyamvada; Kneib, Jean-Paul; D'Aloisio, Anson; Limousin, Marceau; Richard, Johan; Schimd, Carlo

    2010-08-20

    Current efforts in observational cosmology are focused on characterizing the mass-energy content of the universe. We present results from a geometric test based on strong lensing in galaxy clusters. Based on Hubble Space Telescope images and extensive ground-based spectroscopic follow-up of the massive galaxy cluster Abell 1689, we used a parametric model to simultaneously constrain the cluster mass distribution and dark energy equation of state. Combining our cosmological constraints with those from x-ray clusters and the Wilkinson Microwave Anisotropy Probe 5-year data gives Omega(m) = 0.25 +/- 0.05 and w(x) = -0.97 +/- 0.07, which are consistent with results from other methods. Inclusion of our method with all other available techniques brings down the current 2sigma contours on the dark energy equation-of-state parameter w(x) by approximately 30%.

  15. An H-alpha survey of cluster spirals - Comparison of star formation in clusters and the field

    NASA Technical Reports Server (NTRS)

    Moss, C.; Whittle, M.

    1993-01-01

    In an objective prism survey of eight nearby Abell clusters, we have detected H-alpha emission from 77 out of a total of 201 CGCG spiral galaxies. We find that detection of H alpha emission is approximately independent of galaxy absolute magnitude, distance to the cluster center, and the presence of a bar. However, tidally distorted spirals are much more likely to be detected than undistorted spirals. Furthermore, there is a strong tendency for tidally distorted spirals to have compact nuclear emission rather than more extended disk-wide emission. When compared to field spirals, we find that late-type (Sc and Sc-Irr) cluster spirals have less H alpha emission, while early-type (Sa and Sab) cluster spirals can have significantly enhanced emission. The enhanced emission is most likely to be due to tidally induced star formation from galaxy-galaxy interactions.

  16. Discovery of a fourth arc in Abell 2626 at 610 MHz with the GMRT: spectral properties and possibilities for the origin

    NASA Astrophysics Data System (ADS)

    Kale, Ruta; Gitti, Myriam

    2017-03-01

    We report the discovery of a fourth eastern arc (Arc E) towards the cool-core cluster Abell 2626 using 610 MHz Giant Metrewave Radio Telescope observations. Three arcs towards north, west and south were known from earlier works at 1400 MHz and proposed to have originated in precessing radio jets of the central active galactic nucleus. The 610-1400 MHz integrated spectral indices of the arcs are in the range 3.2-3.6 and the spectral index map shows uniform distribution along the lengths of the arcs. If associated with A2626, the arcs have linear extents in the range 79-152 kpc. The detection of Arc E favours the scenario in which a pair of bipolar precessing jets were active and halted to produce the arc system. Based on the morphological symmetry and spectral similarity, we indicate a possible role of gravitational lensing. Further, high-resolution low-frequency observations and measurements of the mass of the system are needed to disentangle the mystery of this source.

  17. Cygnus Loop Supernova Blast Wave

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar 'bullet' traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2,600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30,000 to 60,000 degrees Celsius (50,000 to 100,000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to

  18. Applications for edge detection techniques using Chandra and XMM-Newton data: galaxy clusters and beyond

    NASA Astrophysics Data System (ADS)

    Walker, S. A.; Sanders, J. S.; Fabian, A. C.

    2016-09-01

    The unrivalled spatial resolution of the Chandra X-ray observatory has allowed many breakthroughs to be made in high-energy astrophysics. Here we explore applications of Gaussian gradient magnitude (GGM) filtering to X-ray data, which dramatically improves the clarity of surface brightness edges in X-ray observations, and maps gradients in X-ray surface brightness over a range of spatial scales. In galaxy clusters, we find that this method is able to reveal remarkable substructure behind the cold fronts in Abell 2142 and Abell 496, possibly the result of Kelvin-Helmholtz instabilities. In Abell 2319 and Abell 3667, we demonstrate that the GGM filter can provide a straightforward way of mapping variations in the widths and jump ratios along the lengths of cold fronts. We present results from our ongoing programme of analysing the Chandra and XMM-Newton archives with the GGM filter. In the Perseus cluster, we identify a previously unseen edge around 850 kpc from the core to the east, lying outside a known large-scale cold front, which is possibly a bow shock. In MKW 3s we find an unusual `V' shape surface brightness enhancement starting at the cluster core, which may be linked to the AGN jet. In the Crab nebula a new, moving feature in the outer part of the torus is identified which moves across the plane of the sky at a speed of ˜0.1c, and lies much further from the central pulsar than the previous motions seen by Chandra.

  19. Astrometry With the Hubble Space Telescope: Trigonometric Parallaxes of Planetary Nebula Nuclei NGC 6853, NGC 7293, ABELL 31, and DeHt 5

    NASA Technical Reports Server (NTRS)

    Benedict, G. F.; McArthur, Barbara E.; Napiwotzki, Ralf; Harrison, Thomas E.; Harris, Hugh C.; Nelan, Edmund; Bond, Howard E; Patterson, Richard J.; Ciardullo, Robin

    2009-01-01

    We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1r and FGS 3, white-light interferometers on the Hubble Space Telescope. Proper motions, spectral classifications and VJHKT2M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, sigma (sub pi)/ pi = 5%. Derived distances are: d(sub NGC6853) = 405(exp +28 sub -25) pc, d(sub NGC7293) = 216(exp +14 sub -12) pc, d(sub Abell31) = 621(exp +91 sub -70) pc, and d(sub DeHt5) = 345(exp +19 sub -17) pc. These PNNi distances are all smaller than previously derived from spectroscopic analyses of the central stars. To obtain absolute magnitudes from these distances requires estimates of interstellar extinction. We average extinction measurements culled from the literature, from reddening based on PNNi intrinsic colors derived from model SEDs, and an assumption that each PNN experiences the same rate of extinction as a function of distance as do the reference stars nearest (in angular separation) to each central star. We also apply Lutz-Kelker bias corrections. The absolute magnitudes and effective temperatures permit estimates of PNNi radii through both the Stefan-Boltzmann relation and Eddington fluxes. Comparing absolute magnitudes with post-AGB models provides mass estimates. Masses cluster around 0.57 solar Mass, close to the peak of the white dwarf mass distribution. Adding a few more PNNi with well

  20. Astrometry with the Hubble Space Telescope: Trigonometric Parallaxes of Planetary Nebula Nuclei NGC 6853, NGC 7293, Abell 31, and DeHt 5

    NASA Astrophysics Data System (ADS)

    Benedict, G. Fritz; McArthur, Barbara E.; Napiwotzki, Ralf; Harrison, Thomas E.; Harris, Hugh C.; Nelan, Edmund; Bond, Howard E.; Patterson, Richard J.; Ciardullo, Robin

    2009-12-01

    We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1r and FGS 3, white-light interferometers on the Hubble Space Telescope. Proper motions, spectral classifications and VJHKT2M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, σπ/π = 5%. Derived distances are: d NGC 6853 = 405+28 -25 pc, d NGC 7293 = 216+14 -12 pc, d Abell 31 = 621+91 -70 pc, and d DeHt 5 = 345+19 -17 pc. These PNNi distances are all smaller than previously derived from spectroscopic analyses of the central stars. To obtain absolute magnitudes from these distances requires estimates of interstellar extinction. We average extinction measurements culled from the literature, from reddening based on PNNi intrinsic colors derived from model SEDs, and an assumption that each PNN experiences the same rate of extinction as a function of distance as do the reference stars nearest (in angular separation) to each central star. We also apply Lutz-Kelker bias corrections. The absolute magnitudes and effective temperatures permit estimates of PNNi radii through both the Stefan-Boltzmann relation and Eddington fluxes. Comparing absolute magnitudes with post-AGB models provides mass estimates. Masses cluster around 0.57 M_{⊙}, close to the peak of the white dwarf mass distribution. Adding a few more PNNi with well-determined distances and masses, we compare all the PNNi with cooler white dwarfs

  1. Gamma-ray constraints on supernova nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Leising, Mark D.

    1994-01-01

    Gamma-ray spectroscopy holds great promise for probing nucleosynthesis in individual supernova explosions via short-lived radioactivity, and for measuring current global Galactic supernova nucleosynthesis with longer-lived radioactivity. It was somewhat surprising that the former case was realized first for a Type II supernova, when both Co-56 and Co-57 were detected in SN 1987A. These provide unprecedented constraints on models of Type II explosions and nucleosynthesis. Live Al-26 in the Galaxy might come from Type II supernovae, and if it is eventually shown to be so, can constrain massive star evolution, supernova nucleosynthesis, and the Galactic Type II supernova rate. Type Ia supernovae, thought to be thermonuclear explosions, have not yet been detected in gamma-rays. This is somewhat surprising given current models and recent Co-56 detection attempts. Ultimately, gamma-ray measurements can confirm their thermonuclear nature, probe the nuclear burning conditions, and help evaluate their contributions to Galactic nucleosynthesis. Type Ib/c supernovae are poorly understood. Whether they are core collapse or thermonuclear events might be ultimately settled by gamma-ray observations. Depending on details of the nuclear processing, any of these supernova types might contribute to a detectable diffuse glow of Fe-60 gamma-ray lines. Previous attempts at detection have come very close to expected emission levels. Remnants of any type of age less that a few centuries might be detectable as individual spots of Ti-44 gamma-ray line emission. It is in fact quite surprising that previous surveys have not discovered such spots, and the constraints on the combination of nucleosynthesis yields and supernova rates are very interesting. All of these interesting limits and possibilities mean that the next mission, International Gamma-Ray Astrophysics Laboratory (INTEGRAL), if it has sufficient sensitivity, is very likely to lead to the realization of much of the great potential

  2. FIR Emission From Rich Clusters

    NASA Astrophysics Data System (ADS)

    Cox, Caroline

    1994-12-01

    Previous searches for far infrared (FIR) emission from dominant cluster galaxies using small, X-ray selected samples have found 20% to 50% of clusters to have significant FIR emission. In a new study, I have analyzed the 60microns and 100microns emission properties of cD galaxies in a complete sample of 163 Abell Clusters. For comparison, a control sample of 207 blank fields was analyzed to determine the distribution of spurious detections, which is greater than expected from Gaussian statistics. The contribution of Galactic cirrus at 60 microns and 100 microns to non-Gaussian noise is clearly demonstrated by the correspondence of a 98% confidence level to a signal to noise of 4 or 4.5 rather than to a signal to noise of 2 as expected from Gaussian statistics. After correcting for contaminated fields and spurious signals, I find that about 10% of cD galaxies in rich clusters are sources of FIR emission. Typical detected cDs have FIR luminosities of about 3 times 10(44) erg sec(-1) , which is comparable to the blue luminosities from these objects and an order of magnitude greater than the X-ray luminosities produced in the cores of clusters. Dust masses derived from the 60microns and 100 microns fluxes are ~ 10(7) M _sun. Because only about 10% of the clusters have high FIR luminosities, such strong emission is probably a transient state for an individual cluster. It has been suggested that this FIR emission is due to dust heated by electron collisions from the hot gas that dominates the intra-cluster medium. Study of the optical and X-ray properties of these clusters allows us to test models for the heating process of the dust, the origin of the dust, and its importance as a mechanism for cooling the hot gas. The central electron density and the temperature distribution for the hot gas are determined from analysis of ROSAT PSPC observations of four of these clusters. My program of UBVI imaging is designed to identify dust lanes and morphology that might indicate

  3. The cluster distribution as a test of dark matter models - I. Clustering properties

    NASA Astrophysics Data System (ADS)

    Borgani, Stefano; Plionis, Manolis; Coles, Peter; Moscardini, Lauro

    1995-12-01

    We present extended simulations of the large-scale distribution of galaxy clusters in several dark matter models, using an optimized version of the truncated Zel'dovich approximation (TZA). In order to test the reliability of our simulations, we compare them with N-body-based cluster simulations. We find that the TZA provides a very accurate description of the cluster distribution as long as fluctuations on the cluster mass-scale are in the mildly non-linear regime (sigma_8<~1). The low computational cost of this simulation technique allows us to run a large ensemble of 50 realizations for each model, so we are able to quantify accurately the effects of cosmic variance. Six different dark matter models are studied in this work: standard CDM (SCDM), tilted CDM (TCDM) with primordial spectral index n=0.7, cold+hot DM (CHDM) with Omega_hot=0.3, low Hubble constant (h=0.3) CDM (LOWH), and two spatially flat low-density CDM models with Omega_0=0.2 and Omega_Lambda=0.8, having two different normalizations, sigma_8=0.8 (LambdaCDM_1) and sigma_8=1.3 (LambdaCDM_2). We compare the cluster simulations with an extended redshift sample of Abell/ACO clusters, using various statistical measures, such as the integral of the two-point correlation function, J_3, and the probability density function (pdf). We find that the models that best reproduce the clustering of the Abell/ACO cluster sample are the CHDM and the LambdaCDM_1 models. The LambdaCDM_2 model is too strongly clustered, and this clustering is probably overestimated in our simulations as a result of the large sigma_8-value of this model. All of the other models are ruled out at a high confidence level. The pdfs of all models are well approximated by a lognormal distribution, consistent with similar findings for Abell/ACO clusters. The low-order moments of all the pdfs are found to obey a variance-skewness relation of the form gamma~=S_3sigma^4, with S_3~=1.9, independent of the primordial spectral shape and consistent

  4. XMM Newton Observations of Toothbrush Cluster

    NASA Astrophysics Data System (ADS)

    Kara, Sinancan; Nihal Ercan, Enise; De Plaa, Jelle; Mernier, Francois

    2016-07-01

    Galaxy clusters are the largest gravitationally-bound objects in the universe. The member galaxies are embedded in a hot X-ray emitting Intra-Cluster Medium (ICM) that has been enriched over time with metals produced by supernovae. In this presentation we show new results from XMM-Newton regarding the merging cluster 1RXSJ0603.3+4213. This cluster, also known as the Toothbrush cluster, shows a large toothbrush-shaped radio relic associated with a merger shock North of the cluster core. We show the distribution and the abundances of the metals in this merging cluster in relation to the merger shock. The results are derived from spatially resolved X-ray spectra from the EPIC instrument aboard XMM-Newton.

  5. The Carnegie Supernova Project: Intrinsic colors of type Ia supernovae

    SciTech Connect

    Burns, Christopher R.; Persson, S. E.; Freedman, Wendy L.; Madore, Barry F.; Stritzinger, Maximilian; Contreras, Carlos; Phillips, M. M.; Hsiao, E. Y.; Boldt, Luis; Campillay, Abdo; Castellón, Sergio; Morrell, Nidia; Salgado, Francisco; Folatelli, Gaston; Suntzeff, Nicholas B.

    2014-07-01

    We present an updated analysis of the intrinsic colors of Type Ia supernova (SNe Ia) using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of 'normal' SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B – V light-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of R{sub V} , though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, R{sub V} , and the color excess, E(B – V), such that larger E(B – V) tends to favor lower R{sub V} . The intrinsic u-band colors show a relatively large scatter that cannot be explained by variations in R{sub V} or by the Goobar power-law for circumstellar dust, but rather is correlated with spectroscopic features of the supernova and is therefore likely due to metallicity effects.

  6. Search for gamma ray lines from supernovae and supernova remnants

    NASA Technical Reports Server (NTRS)

    Chupp, E. L.; Forrest, D. J.; Suri, A. N.; Adams, R.; Tsai, C.

    1974-01-01

    A gamma ray monitor with a NaI crystal shielded with a cup-shaped CsI cover was contained in the rotating wheel compartment of the OSO-7 spacecraft for measuring the gamma ray spectra from 0.3 to 10 MeV in search for gamma ray lines from a possible remnant in the Gum Nebula and the apparent Type I supernovae in NGC5253. A brief analysis of data yielded no positive indications for X-rays, gamma ray lines, or continuum from these sources.

  7. Two possible active supernovae in IC 2150

    NASA Astrophysics Data System (ADS)

    Parker, Stu; Bock, Greg; Marples, Peter; Drescher, Colin; Pearl, Patrick; BOSS Team; Contreras, Carlos; Phillips, Mark; Morrell, Nidia; Hsiao, Eric; Carnegie Supernova Project

    2016-03-01

    Stu Parker and the BOSS team report the discovery of a rare event involving two possible active supernovae in IC 2150 (z=0.010404; NED) which were recorded in images obtained by Stu Parker during the ongoing program by the Backyard Observatory Supernova Search (BOSS) team.

  8. Gamma line radiation from supernovae. [nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Arnett, W. D.

    1978-01-01

    Recent calculations of core collapse or massive stars result in explosive ejection of the mantle by a reflected shock. These hydrodynamic results are important for predictions of explosive nucleosynthesis and gamma-ray line emission from supernovae. Previous estimates, based on simple parameterized models or the nucleosynthesis in an average supernova, are compared with these latest results.

  9. Single Degenerate Progenitors of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Bours, Madelon; Toonen, Silvia; Nelemans, Gijs

    2013-01-01

    There is a general agreement that Type Ia supernovae correspond to the thermonuclear runaway of a white dwarf (WD) in a compact binary. The details of these progenitor systems are still unclear. Using the population synthesis code SeBa and several assumption for the WD retention efficiency, we estimate the delay times and supernova rates for the single degenerate scenario.

  10. Rates and progenitors of type Ia supernovae

    SciTech Connect

    Wood-Vasey, William Michael

    2004-01-01

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for

  11. An efficient and fast parallel method for Volterra integral equations of Abel type

    NASA Astrophysics Data System (ADS)

    Capobianco, Giovanni; Conte, Dajana

    2006-05-01

    In this paper we present an efficient and fast parallel waveform relaxation method for Volterra integral equations of Abel type, obtained by reformulating a nonstationary waveform relaxation method for systems of equations with linear coefficient constant kernel. To this aim we consider the Laplace transform of the equation and here we apply the recurrence relation given by the Chebyshev polynomial acceleration for algebraic linear systems. Back in the time domain, we obtain a three term recursion which requires, at each iteration, the evaluation of convolution integrals, where only the Laplace transform of the kernel is known. For this calculation we can use a fast convolution algorithm. Numerical experiments have been done also on problems where it is not possible to use the original nonstationary method, obtaining good results in terms of improvement of the rate of convergence with respect the stationary method.

  12. Television documentary, history and memory. An analysis of Sergio Zavoli's The Gardens of Abel

    PubMed Central

    Foot, John

    2014-01-01

    This article examines a celebrated documentary made for Italian state TV in 1968 and transmitted in 1969 to an audience of millions. The programme – The Gardens of Abel – looked at changes introduced by the radical psychiatrist Franco Basaglia in an asylum in the north-east of Italy (Gorizia). The article examines the content of this programme for the first time, questions some of the claims that have been made for it, and outlines the sources used by the director, Sergio Zavoli. The article argues that the film was as much an expression of Zavoli's vision and ideas as it was linked to those of Franco Basaglia himself. Finally, the article highlights the way that this programme has become part of historical discourse and popular memory. PMID:25937804

  13. Television documentary, history and memory. An analysis of Sergio Zavoli's The Gardens of Abel.

    PubMed

    Foot, John

    2014-10-20

    This article examines a celebrated documentary made for Italian state TV in 1968 and transmitted in 1969 to an audience of millions. The programme - The Gardens of Abel - looked at changes introduced by the radical psychiatrist Franco Basaglia in an asylum in the north-east of Italy (Gorizia). The article examines the content of this programme for the first time, questions some of the claims that have been made for it, and outlines the sources used by the director, Sergio Zavoli. The article argues that the film was as much an expression of Zavoli's vision and ideas as it was linked to those of Franco Basaglia himself. Finally, the article highlights the way that this programme has become part of historical discourse and popular memory.

  14. Inhibition of α-glucosidase by polysaccharides from the fruit hull of Camellia oleifera Abel.

    PubMed

    Zhang, Sheng; Li, Xiang-Zhou

    2015-01-22

    We isolated and purified polysaccharides from the Camellia oleifera Abel. fruit hull and studied its hypoglycemic potential. Our results revealed six polysaccharides (CFPA-1-5 & CFPB) from the aqueous extract from the defatted C. oleifera fruit hull. Purified polysaccharides (purity >90%) were investigated for the inhibition of α-glucosidase activity in vitro. Two polysaccharides, CFPB and CFPA-3 were present in high concentration in the fruit hull and showed a dose-dependent inhibition of α-glucosidase activity, with IC50 concentrations of 11.80 and 10.95 μg/mL, respectively. This result suggests that polysaccharides (CFP) extracted from the fruit hull of C. oleifera may have potential as functional foods with featuring a hypoglycemic effect.

  15. Beneficial Effects of Camellia Oil (Camellia oleifera Abel.) on Hepatoprotective and Gastroprotective Activities.

    PubMed

    Cheng, Yu-Ting; Lu, Chi-Cheng; Yen, Gow-Chin

    2015-01-01

    Epidemiological studies have shown that increased dietary intake of natural antioxidants is beneficial for health because of their bioactivities, including antioxidant and anti-inflammation actions. Camellia oil made from tea seed (Camellia oleifera Abel.) is commonly used as an edible oil and a traditional medicine in Taiwan and China. Until now, the camellia oil has been widely considered as a dietary oil for heath. In this review, we summarize the protective effects of camellia oil with antioxidant activity against oxidative stress leading to hepatic damage and gastrointestinal ulcers. The information in this review leads to the conclusion that camellia oil is not only an edible oil but also a vegetable oil with a potential function for human health.

  16. Supernova shock breakout from a red supergiant.

    PubMed

    Schawinski, Kevin; Justham, Stephen; Wolf, Christian; Podsiadlowski, Philipp; Sullivan, Mark; Steenbrugge, Katrien C; Bell, Tony; Röser, Hermann-Josef; Walker, Emma S; Astier, Pierre; Balam, Dave; Balland, Christophe; Carlberg, Ray; Conley, Alex; Fouchez, Dominique; Guy, Julien; Hardin, Delphine; Hook, Isobel; Howell, D Andrew; Pain, Reynald; Perrett, Kathy; Pritchet, Chris; Regnault, Nicolas; Yi, Sukyoung K

    2008-07-11

    Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic "core-collapse" supernova. Such events are usually only detected at least a few days after the star has exploded. Observations of the supernova SNLS-04D2dc with the Galaxy Evolution Explorer space telescope reveal a radiative precursor from the supernova shock before the shock reached the surface of the star and show the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve confirm that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a way to probe the physics of core-collapse supernovae and the internal structures of their progenitor stars.

  17. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1989-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more than 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  18. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1988-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more that 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  19. Four Papers by the Supernova Cosmology Project

    SciTech Connect

    Perlmutter, S.; et al.

    1995-06-01

    Our search for high-redshift Type Ia supernovae discovered, in its first years, a sample of seven supernovae. Using a 'batch' search strategy, almost all were discovered before maximum light and were observed over the peak of their light curves. The spectra and light curves indicate that almost all were Type Ia supernovae at redshifts z = 0.35 - 0.5. These high-redshift supernovae can provide a distance indicator and 'standard clock' to study the cosmological parameters q{sub 0}, {Lambda}, {Omega}{sub 0}, and H{sub 0}. This presentation and the following presentations of Kim et al. (1996), Goldhaber et al. (1996), and Pain et al. (1996) will discuss observation strategies and rates, analysis and calibration issues, the sources of measurement uncertainty, and the cosmological implications, including bounds on q{sub 0}, of these first high-redshift supernovae from our ongoing search.

  20. Supernovae and cosmology with future European facilities.

    PubMed

    Hook, I M

    2013-06-13

    Prospects for future supernova surveys are discussed, focusing on the European Space Agency's Euclid mission and the European Extremely Large Telescope (E-ELT), both expected to be in operation around the turn of the decade. Euclid is a 1.2 m space survey telescope that will operate at visible and near-infrared wavelengths, and has the potential to find and obtain multi-band lightcurves for thousands of distant supernovae. The E-ELT is a planned, general-purpose ground-based, 40-m-class optical-infrared telescope with adaptive optics built in, which will be capable of obtaining spectra of type Ia supernovae to redshifts of at least four. The contribution to supernova cosmology with these facilities will be discussed in the context of other future supernova programmes such as those proposed for DES, JWST, LSST and WFIRST.

  1. Astrometry With the Hubble Space Telescope: Trigonometric Parallaxes of Planetary Nebula Nuclei NGC 6853, NGC 7293, ABELL 31, and DeHt 5

    DTIC Science & Technology

    2009-12-01

    reserved. Printed in the U.S.A. ASTROMETRY WITH THE HUBBLE SPACE TELESCOPE: TRIGONOMETRIC PARALLAXES OF PLANETARY NEBULA NUCLEI NGC 6853, NGC 7293, ABELL 31...present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix...Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi

  2. The Interaction of Radio Sources and X-ray-Emitting Gas in Cluster Cooling Flows

    NASA Astrophysics Data System (ADS)

    Blanton, Elizabeth L.

    2001-10-01

    Recent Chandra observations of cooling flow clusters containing central radio sources reveal an anti-correlation between radio and X-ray emission. Abell 2052 is one such cluster that exhibits this morphology. The cD galaxy at the center of Abell 2052 is host to the powerful radio source 3C 317. "Holes" in the X-ray emission are coincident with the radio lobes which are surrounded by bright "shells" of X-ray emission. Heating by central radio sources has been proposed as one solution to the "missing gas" in cooling flows -- there is a lack of gas detected in the X-ray at temperatures at or below approximately 1 keV. However, the gas surrounding the radio source in Abell 2052 is cool. The data are consistent with the radio source displacing and compressing, and at the same time being confined by, the X-ray gas. The compression of the X-ray shells appears to have been relatively gentle and, at most, slightly transonic. The pressure in the X-ray gas (the shells and surrounding cooler gas) is approximately an order of magnitude higher than the minimum pressure derived for the radio source, suggesting that an additional source of pressure is needed to support the radio plasma. The compression of the X-ray shells has speeded up the cooling of the shells, and optical emission line filaments are found coincident with the brightest regions of the shells.

  3. Cluster Headache

    MedlinePlus

    Cluster headache Overview By Mayo Clinic Staff Cluster headaches, which occur in cyclical patterns or clusters, are one of the most painful types of headache. A cluster headache commonly awakens you ...

  4. Constraining the Evolution of Poor Clusters

    NASA Astrophysics Data System (ADS)

    Broming, Emma J.; Fuse, C. R.

    2012-01-01

    There currently exists no method by which to quantify the evolutionary state of poor clusters (PCs). Research by Broming & Fuse (2010) demonstrated that the evolution of Hickson compact groups (HCGs) are constrained by the correlation between the X-ray luminosities of point sources and diffuse gas. The current investigation adopts an analogous approach to understanding PCs. Plionis et al. (2009) proposed a theory to define the evolution of poor clusters. The theory asserts that cannibalism of galaxies causes a cluster to become more spherical, develop increased velocity dispersion and increased X-ray temperature and gas luminosity. Data used to quantify the evolution of the poor clusters were compiled across multiple wavelengths. The sample includes 162 objects from the WBL catalogue (White et al. 1999), 30 poor clusters in the Chandra X-ray Observatory archive, and 15 Abell poor clusters observed with BAX (Sadat et al. 2004). Preliminary results indicate that the cluster velocity dispersion and X-ray gas and point source luminosities can be used to highlight a weak correlation. An evolutionary trend was observed for multiple correlations detailed herein. The current study is a continuation of the work by Broming & Fuse examining point sources and their properties to determine the evolutionary stage of compact groups, poor clusters, and their proposed remnants, isolated ellipticals and fossil groups. Preliminary data suggests that compact groups and their high-mass counterpart, poor clusters, evolve along tracks identified in the X-ray gas - X-ray point source relation. While compact groups likely evolve into isolated elliptical galaxies, fossil groups display properties that suggest they are the remains of fully coalesced poor clusters.

  5. Dark matter triggers of supernovae

    NASA Astrophysics Data System (ADS)

    Graham, Peter W.; Rajendran, Surjeet; Varela, Jaime

    2015-09-01

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to 1.25 M⊙ rules out primordial black holes with masses ˜1019- 1020 gm as a dominant constituent of the local dark matter density. Black holes with masses as large as 1024 gm will be excluded if recent observations by the NuStar Collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range 1020- 1022 gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism proposed in this paper can constrain a variety of other dark matter scenarios such as Q balls, annihilation/collision of large composite states of dark matter and models of dark matter where the accretion of dark matter leads to the formation of compact cores within the star. White dwarfs, with their astronomical lifetimes and sizes, can thus act as large spacetime volume detectors enabling a unique probe of the properties of dark matter, especially of dark matter candidates that have low number density. This mechanism also raises the intriguing possibility that a class of supernova may be triggered through rare events induced by dark matter rather than the conventional mechanism of accreting white dwarfs that explode upon reaching the Chandrasekhar mass.

  6. Spectroscopy for E and S0 galaxies in nine clusters

    NASA Astrophysics Data System (ADS)

    Jorgensen, Inger; Franx, Marijn; Kjaergaard, Per

    1995-10-01

    Central velocity dispersions, Mg_2 line indices and radial velocities for 220 E and S0 galaxies are derived on the basis of intermediate resolution spectroscopy. Galaxies in the following clusters have been observed: Abell 194, Abell 539, Abell 3381, Abell 3574, S639, S753, Doradus, HydraI (Abell 1060) and Grm 15. For 151 of the galaxies, the velocity dispersion has not previously been measured. 134 of the Mg_2 determinations are for galaxies with no previous measurement. The spectra cover either 500 or 1000A, centred on the magnesium triplet at 5177A. The observations were obtained with the Boller & Chivens spectrograph at the ESO 1.5-m telescope and with the OPTOPUS, a multi-object fibre-fed B&C spectrograph, at the ESO 3.6-m telescope. The data are part of our ongoing study of the large-scale motions in the Universe and the physical background for the Fundamental Plane. The Fourier fitting method was used to derive the velocity dispersions and radial velocities. The velocity dispersions have been corrected for the effect of the size of the aperture. The correction was established on the basis of velocity dispersion profiles available in the literature. A comparison with results from Davies et al. shows that the derived central velocity dispersions have an rms error of 0.036 in logsigma. There is no offset relative to the velocity dispersions from Davies et al. The offset relative to data from Lucey & Carter is -0.017+/-0.011 in logsigma, with our velocity dispersions being the smallest. The velocity dispersions derived from the B&C and the OPTOPUS observations, as well as the velocity dispersions published by Davies et al., Dressler, Lucey & Carter and Lucey et al., can be brought on a system consistent within 3 per cent. The Mg_2 line indices have been corrected for the size of the apertures, transformed to the Lick system, and corrected for the effect of the velocity dispersion. From comparison with data from Davies et al. and from Faber, we find that the rms

  7. A Cluster and a Sea of Galaxies

    NASA Astrophysics Data System (ADS)

    2010-05-01

    A new wide-field image released today by ESO displays many thousands of distant galaxies, and more particularly a large group belonging to the massive galaxy cluster known as Abell 315. As crowded as it may appear, this assembly of galaxies is only the proverbial "tip of the iceberg", as Abell 315 - like most galaxy clusters - is dominated by dark matter. The huge mass of this cluster deflects light from background galaxies, distorting their observed shapes slightly. When looking at the sky with the unaided eye, we mostly only see stars within our Milky Way galaxy and some of its closest neighbours. More distant galaxies are just too faint to be perceived by the human eye, but if we could see them, they would literally cover the sky. This new image released by ESO is both a wide-field and long-exposure one, and reveals thousands of galaxies crowding an area on the sky roughly as large as the full Moon. These galaxies span a vast range of distances from us. Some are relatively close, as it is possible to distinguish their spiral arms or elliptical halos, especially in the upper part of the image. The more distant appear just like the faintest of blobs - their light has travelled through the Universe for eight billion years or more before reaching Earth. Beginning in the centre of the image and extending below and to the left, a concentration of about a hundred yellowish galaxies identifies a massive galaxy cluster, designated with the number 315 in the catalogue compiled by the American astronomer George Abell in 1958 [1]. The cluster is located between the faint, red and blue galaxies and the Earth, about two billion light-years away from us. It lies in the constellation of Cetus (the Whale). Galaxy clusters are some of the largest structures in the Universe held together by gravity. But there is more in these structures than the many galaxies we can see. Galaxies in these giants contribute to only ten percent of the mass, with hot gas in between galaxies

  8. Models for Type I supernovae

    SciTech Connect

    Woosley, S.E.; Weaver, T.A.; Taam, R.E.

    1980-06-17

    Two rather disjoint scenarios for Type I supernovae are presented. One is based upon mass accretion by a white dwarf in a binary system. The second involves a star having some 8 to 10 times the mass of the sun which may or may not be a solitary star. Despite the apparent dissimilarities in the models it may be that each occurs to some extent in nature for they both share the possibility of producing substantial quantities of /sup 56/Ni and explosions in stars devoid of hydrogen envelopes. These are believed to be two properties that must be shared by any viable Type I model.

  9. SNRPy: Supernova remnant evolution modeling

    NASA Astrophysics Data System (ADS)

    Leahy, Denis A.; Williams, Jacqueline

    2017-03-01

    SNRPy (Super Nova Remnant Python) models supernova remnant (SNR) evolution and is useful for understanding SNR evolution and to model observations of SNR for obtaining good estimates of SNR properties. It includes all phases for the standard path of evolution for spherically symmetric SNRs and includes alternate evolutionary models, including evolution in a cloudy ISM, the fractional energy loss model, and evolution in a hot low-density ISM. The graphical interface takes in various parameters and produces outputs such as shock radius and velocity vs. time, SNR surface brightness profile and spectrum.

  10. The LCOGT Supernova Key Project

    NASA Astrophysics Data System (ADS)

    Howell, Dale Andrew; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis; Valenti, Stefano; LCOGT Supernova Key Project

    2016-06-01

    We highlight results from the Las Cumbres Observatory Global Telescope (LCOGT) Supernova Key Project -- a 3 year program to obtain lightcurves and spectra of approximately 500 low-redshift SNe. LCOGT is a robotic network of elevent one and two meter telescopes spaced around the globe. We are involved in a variety of surveys, including the intermediate Palomar Transient Factory, LaSilla Quest, PESSTO, and KMTNet. Recent results include analysis of large samples of core-collaspe SNe, the largest sample of SNe Ibn, evidence of the progenitors of SNe Ia from companion shocking, and new findings about superluminious SNe.

  11. Petascale Supernova Simulation with CHIMERA

    SciTech Connect

    Messer, Bronson; Bruenn, S. W.; Blondin, J. M.; Mezzacappa, Anthony; Hix, William Raphael; Dirk, Charlotte

    2007-01-01

    CHIMERA is a multi-dimensional radiation hydrodynamics code designed to study core-collapse supernovae. The code is made up of three essentially independent parts: a hydrodynamics module, a nuclear burning module, and a neutrino transport solver combined within an operator-split approach. We describe some ma jor algorithmic facets of the code and briefly discuss some recent results. The multi-physics nature of the problem, and the specific implementation of that physics in CHIMERA, provide a rather straightforward path to effective use of multi-core platforms in the near future.

  12. A doubly robotic telescope - The Berkeley Automated Supernova Search

    NASA Technical Reports Server (NTRS)

    Perlmutter, Saul; Muller, Richard A.; Newberg, Heidi J. M.; Pennypacker, Carlton R.; Sasseen, Timothy P.; Smith, Craig K.

    1992-01-01

    We have designed, built, and are successfully using a completely robotic supernova search, with an automated observatory and automated real-time analysis and scheduling. This system has detected 20 supernovae so far, resulting in early supernova observations, surprising supernova rates, and new evidence against a true 'inclination effect' in galaxies.

  13. The ALMA Frontier Fields Survey. I. 1.1 mm continuum detections in Abell 2744, MACS J0416.1-2403 and MACS J1149.5+2223

    NASA Astrophysics Data System (ADS)

    González-López, J.; Bauer, F. E.; Romero-Cañizales, C.; Kneissl, R.; Villard, E.; Carvajal, R.; Kim, S.; Laporte, N.; Anguita, T.; Aravena, M.; Bouwens, R. J.; Bradley, L.; Carrasco, M.; Demarco, R.; Ford, H.; Ibar, E.; Infante, L.; Messias, H.; Muñoz Arancibia, A. M.; Nagar, N.; Padilla, N.; Treister, E.; Troncoso, P.; Zitrin, A.

    2017-01-01

    Context. Dusty star-forming galaxies are among the most prodigious systems at high redshift (z > 1), characterized by high star-formation rates and huge dust reservoirs. The bright end of this population has been well characterized in recent years, but considerable uncertainties remain for fainter dusty star-forming galaxies, which are responsible for the bulk of star formation at high redshift and thus play a key role in galaxy growth and evolution. Aims: In this first paper of our series, we describe our methods for finding high redshift faint dusty galaxies using millimeter observations with ALMA. Methods: We obtained ALMA 1.1 mm mosaic images for three strong-lensing galaxy clusters from the Frontier Fields Survey, which constitute some of the best studied gravitational lenses to date. The ≈2' × 2' mosaics overlap with the deep HST WFC3/IR footprints and encompass the high magnification regions of each cluster for maximum intrinsic source sensitivity. The combination of extremely high ALMA sensitivity and the magnification power of these clusters allows us to systematically probe the sub-mJy population of dusty star-forming galaxies over a large surveyed area. Results: We present a description of the reduction and analysis of the ALMA continuum observations for the galaxy clusters Abell 2744 (z = 0.308), MACS J0416.1-2403 (z = 0.396) and MACS J1149.5+2223 (z = 0.543), for which we reach observed rms sensitivities of 55, 59 and 71 μJy beam-1 respectively. We detect 12 dusty star-forming galaxies at S/N ≥ 5.0 across the three clusters, all of them presenting coincidence with near-infrared detected counterparts in the HST images. None of the sources fall close to the lensing caustics, thus they are not strongly lensed. The observed 1.1 mm flux densities for the total sample of galaxies range from 0.41 to 2.82 mJy, with observed effective radii spanning ≲0.̋05 to 0.̋37 ± 0.̋21 . The lensing-corrected sizes of the detected sources appear to be in the

  14. Deep Chandra Observations of the Cool Core Clusters A2052 and A262

    NASA Astrophysics Data System (ADS)

    Blanton, Elizabeth L.; Randall, S. W.; Douglass, E. M.; Clarke, T. E.; Anderson, L. A.; Sarazin, C. L.; McNamara, B. R.

    2008-03-01

    We present deep Chandra observations of the cool core clusters Abell 2052 and Abell 262. New features, including ghost bubbles, ripples, edges, and a tunnel are revealed. Correlations of features seen in the X-ray and radio give evidence for multiple outbursts of the AGN. Comparison of the radio source energy input rates with the ICM cooling rates shows that the radio source can easily offset the cooling in A2052 and is much closer to offsetting the cooling in A262 than was estimated previously. Maps of pressure and temperature will be presented, as well as correlations between surface brightness features and optical-line emission. We constrain the temperature of diffuse, hot gas that may be filling the bubbles and providing pressure support to uphold the cool, dense shells surrounding the bubbles.

  15. Dumb-bell galaxies in southern clusters: Catalog and preliminary statistical results

    NASA Technical Reports Server (NTRS)

    Vettolani, G.; Gregorini, L.; Parma, P.; Deruiter, H. R.

    1990-01-01

    The dominant galaxy of a rich cluster is often an object whose formation and evolution is closely connected to the dynamics of the cluster itself. Hoessel (1980) and Schneider et al. (1983) estimate that 50 percent of the dominant galaxies are either of the dumb-bell type or have companions at projected distances less than 20 kpc, which is far in excess of the number expected from chance projection (see also Rood and Leir 1979). Presently there is no complete sample of these objects, with the exception of the listing of dumb-bell galaxies in BM type I and I-II clusters in the Abell statistical sample of Rood and Leir (1979). Recent dynamical studies of dumb-bell galaxies in clusters (Valentijn and Casertano, 1988) still suffer from inhomogeneity of the sample. The fact that it is a mixture of optically and radio selected objects may have introduced an unknown biases, for instance if the probability of radio emission is enhanced by the presence of close companions (Stocke, 1978, Heckman et al. 1985, Vettolani and Gregorini 1988) a bias could be present in their velocity distribution. However, this situation is bound to improve: a new sample of Abell clusters in the Southern Hemisphere has been constructed (Abell et al., 1988 hereafter ACO), which has several advantages over the original northern catalog. The plate material (IIIaJ plates) is of better quality and reaches fainter magnitudes. This makes it possible to classify the cluster types with a higher degree of accuracy, as well as to fainter magnitudes. The authors therefore decided to reconsider the whole problem constructing a new sample of dumb-bell galaxies homogeneously selected from the ACO survey. Details of the classification criteria are given.

  16. Primordial inhomogeneities in the expanding universe. I - Density and velocity distributions of galaxies in the vicinities of rich clusters

    NASA Technical Reports Server (NTRS)

    Silk, J.; Wilson, M. L.

    1979-01-01

    The density profiles and Hubble flow deviations in the vicinities of rich galaxy clusters are derived for a variety of models of initial density and velocity perturbations at the recombination epoch. The galaxy correlation function, measured with respect to the Abell clusters, is used to normalize the theoretical models. The angular scales of the required primordial inhomogeneities are calculated. It is found that the resulting density profiles around rich clusters are surprisingly insensitive to the shape of the initial perturbations and also to the cosmological density parameter, Omega. However, it is shown that the distribution of galaxy radial velocities can provide a possible means of deriving Omega.

  17. Measuring q sub 0 using supernovae at z approx 0. 3

    SciTech Connect

    Newberg, H.J.M.

    1992-07-01

    The measurement of q{sub o} is extremely important for understanding the quantity of matter in our universe. The measurement of q{sub o} using supernovae of type Ia as standard candles is appealing because it requires less modeling than other methods using galaxies. The challenge with using supernovae to measure q{sub o} is in finding enough of them. In order to find supernovas, we have constructed a very popular f/1 camera for the 3.9m Anglo-Australian Telescope. The camera uses reducing optics that put a 17 in. {times} 17 in. field on a 1024 {times} 1024 pixel Thomson CCD. Using this system, we image to 23rd magnitude in five minutes. We have developed a software package that uses image subtraction to find supernovae that are approximately magnitude 22.4 or brighter in these images. One field can be processed every 6.6 minutes on a relatively unloaded VAX 6000-6510. We estimate that this system should find one supernova in every 105--139 images (about two nights of observation on the AAT). Throughout the two years of operation, we observed the equivalent of about four nights with seeing better than two arc seconds. Although we found many candidates, we were unable to confirm any supemovae. The next generation of this search is currently using the 2.5m Isaac Newton Telescope in the Canary Islands. We have solved many problems encountered with the AAT search by targeting distant clusters of galaxies, by operating at a site that allows higher resolution imaging, and by scheduling follow-up observations. This system, although still in its infancy, has yielded one event that could be a high redshift supernova. We estimate that it will require 36 type Ia supernovae, discovered at or before maximum, to find q{sub o} to within 0.2, and 144 such supernovae to measure q{sub o} within 0.1. Clearly, the program will have to be expanded to find this quantity of supernovae.

  18. Measuring qo using supernovae at z ~ 0.3

    SciTech Connect

    Newberg, Heidi Jo Marvin

    1992-07-01

    The measurement of qo is extremely important for understanding the quantity of matter in our universe. The measurement of qo using supernovae of type Ia as standard candles is appealing because it requires less modeling than other methods using galaxies. The challenge with using supernovae to measure qo is in finding enough of them. In order to find supernovas, we have constructed a very popular f/1 camera for the 3.9m Anglo-Australian Telescope. The camera uses reducing optics that put a 17 in. x 17 in. field on a 1024 x 1024 pixel Thomson CCD. Using this system, we image to 23rd magnitude in five minutes. We have developed a software package that uses image subtraction to find supernovae that are approximately magnitude 22.4 or brighter in these images. One field can be processed every 6.6 minutes on a relatively unloaded VAX 6000-6510. We estimate that this system should find one supernova in every 105--139 images (about two nights of observation on the AAT). Throughout the two years of operation, we observed the equivalent of about four nights with seeing better than two arc seconds. Although we found many candidates, we were unable to confirm any supemovae. The next generation of this search is currently using the 2.5m Isaac Newton Telescope in the Canary Islands. We have solved many problems encountered with the AAT search by targeting distant clusters of galaxies, by operating at a site that allows higher resolution imaging, and by scheduling follow-up observations. This system, although still in its infancy, has yielded one event that could be a high redshift supernova. We estimate that it will require 36 type Ia supernovae, discovered at or before maximum, to find qo to within 0.2, and 144 such supernovae to measure qo within 0.1. Clearly, the program will have to be expanded to find this quantity of supernovae.

  19. The Supernova Remnant CTA 1

    NASA Technical Reports Server (NTRS)

    Seward, Frederick D.

    1996-01-01

    The supernova remnants G327.1-1.1 and G327.4+0.4 (Kes 27) are located 1.5 deg apart in the constellation Norma. In 1980, Einstein IPC observations discovered that both were irregular filled-center X-ray sources with possible point sources superposed. This paper describes new ROSAT position sensitive proportional counter (PSPC) observations which both map the diffuse structure and clearly show several unresolved sources in each field. Both remnants have bright emitting regions inside the limb which might indicate the presence of high energy electrons accelerated by a pulsar. The interior region is more prominent in G327.1-1.1 than in Kes 27. The spectra are relatively strongly absorbed, as expected from distant remnants close to the galactic plane. Comparison of the X-ray and radio maps of each remnant allows us to attribute some emission to a shell and some to the interior. With this information, a blast-wave model is used to derive approximate ages and energy release. Indications are that the Kes 27 supernova deposited approximately 10(exp 51) ergs in the surrounding medium. The G327.1-1.1 event probably deposited a factor of 3-10 less.

  20. Supernova Remnants in High Definition

    NASA Astrophysics Data System (ADS)

    Slane, Patrick; Badenes, Carles; Freyer, Chris; Hughes, Jack; Lee, Herman Shiu-Hang; Lopez, Laura; Patnaude, Daniel; Reynolds, Steve; Temim, Tea; Williams, Brian; Wongwathanarat, Annop; Yamaguchi, Hiroya

    2015-10-01

    As the observable products of explosive stellar death, supernova remnants reveal some of the most direct information on the physics of the explosions, the properties of the progenitor systems, and the demographics of compact objects formed in the supernova events. High sensitivity X-ray observations have allowed us to probe the properties of the shocked plasma, providing constraints on abundances and ionization states that connect directly progenitor masses and metallicities, the nature of the explosions (core-collapse vs. thermonuclear), and the physics of shock heating and particle acceleration in fast shocks. Studies of SNRs in the Magellanic Clouds have provided information on source demographics in a low metallicity environment, and deep searches for point sources in Galactic SNRs imply that many remnants contain rapidly cooling neutron stars or black holes. Based on Chandra observations, we know that crucial measurements required to advance our knowledge in these areas are possible only with much more sensitive observations at high angular resolution. From identifying the effects of particle acceleration on the post-shock gas in young SNRs like Tycho to obtaining spatially resolved spectra - and identifying compact objects - for young SNRs in the Magellanic Clouds, the capabilities of a facility like the X-ray Surveyor are required. Here I present a summary of recent advances brought about by spectral investigations of SNRs, and discuss particular examples of new advances that will be enabled by X-ray Surveyor capabilities.

  1. Gamma ray constraints on the Galactic supernova rate

    NASA Technical Reports Server (NTRS)

    Hartmann, D.; The, L.-S.; Clayton, Donald D.; Leising, M.; Mathews, G.; Woosley, S. E.

    1991-01-01

    We perform Monte Carlo simulations of the expected gamma ray signatures of Galactic supernovae of all types to estimate the significance of the lack of a gamma ray signal due to supernovae occurring during the last millenium. Using recent estimates of the nuclear yields, we determine mean Galactic supernova rates consistent with the historic supernova record and the gamma ray limits. Another objective of these calculations of Galactic supernova histories is their application to surveys of diffuse Galactic gamma ray line emission.

  2. Supernovae: lights in the darkness

    NASA Astrophysics Data System (ADS)

    Every year, at the end of the summer, the Section of Physics and Technique of the "Institut Menorquí d'Estudis" and the "Societat Catalana de Física" organize the "Trobades Científiques de la Mediterrània" with the support of several academic institutions. The 2007 edition has been devoted to stellar explosions, the true evolutionary engines of galaxies. Whenever a star explodes, it injects into the interstellar medium a kinetic energy of 1051 erg and between one and several solar masses of newly synthesized elements as a result of the thermonuclear reactions that have taken place within the stellar interior. Two mechanisms are able to provide these enormous amounts of energy: one of them thermonuclear and the other, gravitational. Thermonuclear supernovae are the result of the incineration of a carbon-oxygen white dwarf that is the compact star of a binary stellar system. If the two stars are sufficiently close to each other, the white dwarf accretes matter from its companion, approaches the mass of Chandrasekhar, and ends up exploding. The processes previous to the explosion, the explosion itself, as well as the exact nature of the double stellar system that explodes, are still a matter of discussion. This point is particularly important because these explosions, known as Type Ia Supernovae, are very homogenous and can be used to measure cosmological distances. The most spectacular result obtained, is the discovery of the accelerated expansion of the Universe, but it still feels uncomfortable that such a fundamental result is based on a "measuring system" whose origin and behaviour in time is unknown. At the end of their lives, massive stars generate an iron nucleus that gets unstable when approaching the Chandrasekhar mass. Its collapse gives rise to the formation of a neutron star or a black hole, and the external manifestation of the energy that is released, about a 1053 erg, consists of a Type II or Ib/c supernova, of a Gamma Ray Burst (GRB) or even of

  3. Energetic Supernovae from the Cosmic Dawn

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung

    2013-04-01

    We present the results from our 3D supernova simulations by using CASTRO, a new radiation-hydrodynamics code. The first generation of stars in the universe ended the cosmic dark age by shining the first light. But what was the fate of these stars? Based on the stellar evolution models, the fate of stars depends on their masses. Modern cosmological simulations suggest that the first stars could be very massive, with a typical mass scale over 50 solar masses. We look for the possible supernovae from the death of the first stars with masses over 50 solar masses. Besides the iron-core collapse supernovae, we find energetic thermonuclear supernovae, including two types of pair-instability supernovae and one type of general-relativity instability supernovae. Our models capture all explosive burning and follow the explosion until the shock breaks out from the stellar surface. We will discuss the energetics, nucleosynthesis, and possible observational signatures for these primordial supernovae that will be the prime targets for future large telescopes such as the James Webb Space Telescope (JWST).

  4. Type Ia Supernova Modeling with Spectrophotometric Data from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Saunders, Clare; Nearby Supernova Factory

    2017-01-01

    Type Ia supernova cosmology is currently limited by dispersion in standardized magnitudes, driven by a combination of calibration uncertainty and so-called ‘intrinsic dispersion.' This intrinsic dispersion is caused by supernova behavior that the current lightcurve fitters do not account for, and it can involve systematic trends. Using data from the Nearby Supernova Factory, we have developed an empirical model that captures a wider range of Type Ia supernova behavior and can be used to improve standardized magnitude dispersion. To do this, Gaussian Processes and Expectation Maximization Factor Analysis are used to generate spectral time series templates that can be combined linearly. Variations of this model are optimized, alternatively for supernova standardization or for maximum accuracy in the description of supernova spectral features. We present these models along with interpretation of the model components. Methods are discussed for the most efficient application of the models in cosmological surveys.

  5. The self-enrichment of globular clusters

    NASA Astrophysics Data System (ADS)

    Morgan, Siobahn; Lake, George

    1989-04-01

    It is shown that protoglobular clusters of primordial gas can confine the supernovae needed to enrich themselves. The required protocluster cloud masses and structural parameters are the same as those currently observed for the clusters. Two causal scenarios for star formation are examined to calculate the initial enrichment of primordial clouds. In the 'Christmas tree' scheme, the maximum final (Fe/H) is about 0.1. Since the time scale for formation and evolution of massive stars at the center of a cluster is nearly an order of magnitude less than the collapse time of the cluster, every globular cluster may have to survive a suprernova detonation. If this is the case, the minimum mass of a globular cluster is about 10 to the 4.6th solar mass.

  6. An Open Catalog for Supernova Data

    NASA Astrophysics Data System (ADS)

    Guillochon, James; Parrent, Jerod; Kelley, Luke Zoltan; Margutti, Raffaella

    2017-01-01

    We present the Open Supernova Catalog, an online collection of observations and metadata for presently 36,000+ supernovae and related candidates. The catalog is freely available on the web (https://sne.space), with its main interface having been designed to be a user-friendly, rapidly searchable table accessible on desktop and mobile devices. In addition to the primary catalog table containing supernova metadata, an individual page is generated for each supernova, which displays its available metadata, light curves, and spectra spanning X-ray to radio frequencies. The data presented in the catalog is automatically rebuilt on a daily basis and is constructed by parsing several dozen sources, including the data presented in the supernova literature and from secondary sources such as other web-based catalogs. Individual supernova data is stored in the hierarchical, human- and machine-readable JSON format, with the entirety of each supernova’s data being contained within a single JSON file bearing its name. The setup we present here, which is based on open-source software maintained via git repositories hosted on github, enables anyone to download the entirety of the supernova data set to their home computer in minutes, and to make contributions of their own data back to the catalog via git. As the supernova data set continues to grow, especially in the upcoming era of all-sky synoptic telescopes, which will increase the total number of events by orders of magnitude, we hope that the catalog we have designed will be a valuable tool for the community to analyze both historical and contemporary supernovae.

  7. Connecting the high- and low-energy Universe: dust processing inside Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Micelotta, Elisabetta; Dwek, Eli; Slavin, Jonathan

    2015-09-01

    The recent detection of large amounts of dust (> 10(7) M_⊙) at very high redshift (z > 6) raises a fundamental question about the origin of such dust. The main dust producers, i. e., the stars populating the Red Giant Branch and the Asymptotic Giant Branch (RGB and AGB stars) did not have time to evolve. From an evolutionary point of view, young supernovae (SNe) could represent a viable source of dust in high-redshift galaxies, however, a critical issue still needs to be addressed. While recent observations have demonstrated that supernovae are indeed efficient dust factories, at the same time SNe represent the major agent responsible for dust destruction. Supernova blast waves propagating into the interstellar medium destroy the dust residing there, while the fresh dust produced by the supernova itself is threatened by the reverse shock which propagates through the expanding ejecta towards the center of the remnant. We focus here on this second destruction mechanism, with the aim of quantifying the amount of dust able to survive the heavy processing by the reverse shock and to reach the interstellar medium. We present our results for the textbook supernova remnant Cassiopeia A (Cas A). Using recent X-ray and infrared observations, we have developed a model for the evolution of the remnant and the simultaneous processing of the dust by the reverse shock, and derived the expected amount of surviving dust. In addition, we will briefly illustrate the impact of the capabilities of the Athena mission on the variety of astrophysical problems involving the processing of dust particles in extreme environments characterized by the presence of shocked X-ray emitting gas. These range from individual supernova remnants, to starburst super winds up to AGN outflows and the hot intra-cluster medium. The study of dust processing by a shocked gas truly connects the high-energy Universe with the low-energy Universe, and Athena will play a major role in it.

  8. Intergalactic Dust and Observations of Type IA Supernovae

    NASA Astrophysics Data System (ADS)

    Aguirre, Anthony

    1999-11-01

    Estimates of the cosmic star formation rate and of cluster metallicities independently imply that at z<~0.5 the gas in the universe has substantial average metallicity: 1/10<~Z/Zsolar<~1/3 for Ωgas=0.05. This metal density probably cannot be contained in known solar-metallicity galaxies of density parameter Ω*~0.004, implying significant enrichment of the intergalactic medium (IGM) by ejection of metals and dust from galaxies via winds, in mergers or in dust efflux driven by radiation pressure. Galaxies have a dust-to-metal ratio of ~0.5 in their interstellar media, but some fraction (1-f)>0 of this must be destroyed in the IGM or during the ejection process. Assuming the Draine & Lee dust model and preferential destruction of small grains (as destruction by sputtering would provide), I calculate the reddening and extinction of a uniform cosmological dust component in terms of f and the minimum grain size amin. Very small grains provide most of the reddening but less than half of the opacity for optical extinction. For f>~0.3 and amin>~0.1 μm, the intergalactic dust would be too gray to have been detected by its reddening, yet dense enough to be cosmologically important: it could account for the recently observed Type Ia supernova dimming at z~0.5 without cosmic acceleration. It would also have implications for galaxy counts and evolutionary studies and would contribute significantly to the cosmic infrared background (CIB). The importance of gray intergalactic dust of the described type can be tested by observations of z=0.5 supernovae in (rest) R-band or longer wavelengths and by the fluxes of a large sample of supernovae at z>1.

  9. Object Classification at the Nearby Supernova Factory

    SciTech Connect

    Aragon, Cecilia R.; Bailey, Stephen; Aragon, Cecilia R.; Romano, Raquel; Thomas, Rollin C.; Weaver, B. A.; Wong, D.

    2007-12-21

    We present the results of applying new object classification techniques to the supernova search of the Nearby Supernova Factory. In comparison to simple threshold cuts, more sophisticated methods such as boosted decision trees, random forests, and support vector machines provide dramatically better object discrimination: we reduced the number of nonsupernova candidates by a factor of 10 while increasing our supernova identification efficiency. Methods such as these will be crucial for maintaining a reasonable false positive rate in the automated transient alert pipelines of upcoming large optical surveys.

  10. Chiral transport of neutrinos in supernovae

    NASA Astrophysics Data System (ADS)

    Yamamoto, Naoki

    2017-03-01

    The conventional neutrino transport theory for core-collapse supernovae misses one key property of neutrinos: the left-handedness. The chirality of neutrinos modifies the hydrodynamic behavior at the macroscopic scale and leads to topological transport phenomena. We argue that such transport phenomena should play important roles in the evolution of core-collapse supernovae, and, in particular, lead to a tendency toward the inverse energy cascade from small to larger scales, which may be relevant to the origin of the supernova explosion.

  11. 3 New Supernova Discoveries/Classifications

    NASA Astrophysics Data System (ADS)

    Nugent, Peter; Sullivan, Mark; Howell, D. Andrew

    2009-08-01

    The Type Ia supernova science working group of the Palomar Transient Factory (ATEL#1964) reports the discovery of three nearby supernova. Confirmation spectra were taken on the Double Beam Spectrograph on the Palomar Hale telescope on August 19 UT by R. Ellis and J. Cooke. Classification of the spectra were carried out using Superfit (Howell et al. 2005). As all three are quite young, STIS/UV spectroscopic observations on the Hubble Space Telescope were triggered by the ToO program "Verifying the Utility of Type Ia Supernovae as Cosmological Probes: Evolution and Dispersion in the Ultraviolet Spectra " (PI: R.

  12. Diffuse neutrino flux from failed supernovae.

    PubMed

    Lunardini, Cecilia

    2009-06-12

    I study the diffuse flux of electron antineutrinos from stellar collapses with direct black hole formation (failed supernovae). This flux is more energetic than that from successful supernovae, and therefore it might contribute substantially to the total diffuse flux above realistic detection thresholds. The total flux might be considerably higher than previously thought, and approach the sensitivity of Super-Kamiokande. For more conservative values of the parameters, the flux from failed supernovae dominates for antineutrino energies above 30-45 MeV, with potential to give an observable spectral distortion at megaton detectors.

  13. Postexplosion hydrodynamics of supernovae in red supergiants

    NASA Technical Reports Server (NTRS)

    Herant, Marc; Woosley, S. E.

    1994-01-01

    Shock propagation, mixing, and clumping are studied in the explosion of red supergiants as Type II supernovae using a two-dimensional smooth particle hydrodynamic (SPH) code. We show that extensive Rayleigh-Talor instabilities develop in the ejecta in the wake of the reverse shock wave. In all cases, the shell structure of the progenitor is obliterated to leave a clumpy, well-mixed supernova remnant. However, the occurrence of mass loss during the lifetime of the progenitor can significantly reduce the amount of mixing. These results are independent of the Type II supernova explosion mechanism.

  14. Supernovae effects on the terrestrial atmosphere

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.; Chandra, S.; Stecher, T. P.

    1980-01-01

    The first effects of a nearby (10 parsec) supernova on the earth's atmosphere will be caused by ultraviolet radiation dissociating molecular oxygen. The event will be of about one month's duration. Several months later nuclear gamma radiation may arrive, causing a decrease in atmospheric ozone. Cosmic radiation from the supernova remnant will not intercept the earth for at least 1000 years at which time ozone will be seriously depleted. Supernova ultraviolet radiation increases column ozone and atomic oxygen. Atmospheric thermal structure is modified with a large temperature increase in the mesosphere and lower thermosphere and a decrease at higher altitudes caused by enhanced heat loss due to atomic oxygen radiation and conduction.

  15. Supernovae and Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Panagia, Nino; Sahu, Kailash

    2001-07-01

    Participants; Preface; Gamma-ray burst-supernova relation B. Paczynski; Observations of gamma-ray bursts G. Fishman; Fireballs T. Piran; Gamma-ray mechanisms M. Rees; Prompt optical emission from gamma-ray bursts R. Kehoe, C. Akerlof, R. Balsano, S. Barthelmy, J. Bloch, P. Butterworth, D. Casperson, T. Cline, S. Fletcher, F. Frontera, G. Gisler, J. Heise, J. Hills, K. Hurley, B. Lee, S. Marshall, T. McKay, A. Pawl, L. Piro, B. Priedhorsky, J. Szymanski and J. Wren; X-ray afterglows of gamma-ray bursts L. Piro; The first year of optical-IR observations of SN1998bw I. Danziger, T. Augusteijn, J. Brewer, E. Cappellaro, V. Doublier, T. Galama, J. Gonzalez, O. Hainaut, B. Leibundgut, C. Lidman, P. Mazzali, K. Nomoto, F. Patat, J. Spyromilio, M. Turatto, J. Van Paradijs, P. Vreeswijk and J. Walsh; X-ray emission of Supernova 1998bw in the error box of GRB980425 E. Pian; Direct analysis of spectra of type Ic supernovae D. Branch; The interaction of supernovae and gamma-ray bursts with their surroundings R. Chevalier; Magnetars, soft gamma-ray repeaters and gamma-ray bursts A. Harding; Super-luminous supernova remnants Y. -H. Chu, C. -H. Chen and S. -P. Lai; The properties of hypernovae: SNe Ic 1998bw, 1997ef, and SN IIn 1997cy K. Nomoto, P. Mazzali, T. Nakamura, K. Iwanmoto, K. Maeda, T. Suzuki, M. Turatto, I. Danziger and F. Patat; Collapsars, Gamma-Ray Bursts, and Supernovae S. Woosley, A. MacFadyen and A. Heger; Pre-supernova evolution of massive stars N. Panagia and G. Bono; Radio supernovae and GRB 980425 K. Weiler, N. Panagia, R. Sramek, S. Van Dyk, M. Montes and C. Lacey; Models for Ia supernovae and evolutionary effects P. Hoflich and I. Dominguez; Deflagration to detonation A. Khokhlov; Universality in SN Iae and the Phillips relation D. Arnett; Abundances from supernovae F. -K. Thielemann, F. Brachwitz, C. Freiburghaus, S. Rosswog, K. Iwamoto, T. Nakamura, K. Nomoto, H. Umeda, K. Langanke, G. Martinez-Pinedo, D. Dean, W. Hix and M. Strayer; Sne, GRBs, and the

  16. Anti-Brownian ELectrokinetic (ABEL) trapping of single β2-adrenergic receptors in the absence and presence of agonist

    NASA Astrophysics Data System (ADS)

    Bockenhauer, Samuel; Fuerstenberg, Alexandre; Yao, Xiao Jie; Kobilka, Brian K.; Moerner, W. E.

    2012-02-01

    The ABEL trap allows trapping of single biomolecules in solution for extended observation without immobilization. The essential idea combines fluorescence-based position estimation with fast electrokinetic feedback in a microfluidic geometry to counter the Brownian motion of a single nanoscale object, hence maintaining its position in the field of view for hundreds of milliseconds to seconds. Such prolonged observation of single proteins allows access to slow dynamics, as probed by any available photophysical observables. We have used the ABEL trap to study conformational dynamics of the β2-adrenergic receptor, a key G-protein coupled receptor and drug target, in the absence and presence of agonist. A single environment-sensitive dye reports on the receptor microenvironment, providing a real-time readout of conformational change for each trapped receptor. The focus of this paper will be a quantitative comparison of the ligandfree and agonist-bound receptor data from our ABEL trap experiments. We observe a small but clearly detectable shift in conformational equilibria and a lengthening of fluctuation timescales upon binding of agonist. In order to quantify the shift in state distributions and timescales, we apply nonparametric statistical tests to place error bounds on the resulting single-molecule distributions.

  17. Supernova relic neutrinos and the supernova rate problem: Analysis of uncertainties and detectability of ONeMg and failed supernovae

    SciTech Connect

    Mathews, Grant J.; Hidaka, Jun; Kajino, Toshitaka; Suzuki, Jyutaro

    2014-08-01

    Direct measurements of the core collapse supernova rate (R{sub SN}) in the redshift range 0 ≤ z ≤ 1 appear to be about a factor of two smaller than the rate inferred from the measured cosmic massive star formation rate (SFR). This discrepancy would imply that about one-half of the massive stars that have been born in the local observed comoving volume did not explode as luminous supernovae. In this work, we explore the possibility that one could clarify the source of this 'supernova rate problem' by detecting the energy spectrum of supernova relic neutrinos with a next generation 10{sup 6} ton water Čerenkov detector like Hyper-Kamiokande. First, we re-examine the supernova rate problem. We make a conservative alternative compilation of the measured SFR data over the redshift range 0 ≤z ≤ 7. We show that by only including published SFR data for which the dust obscuration has been directly determined, the ratio of the observed massive SFR to the observed supernova rate R{sub SN} has large uncertainties ∼1.8{sub −0.6}{sup +1.6} and is statistically consistent with no supernova rate problem. If we further consider that a significant fraction of massive stars will end their lives as faint ONeMg SNe or as failed SNe leading to a black hole remnant, then the ratio reduces to ∼1.1{sub −0.4}{sup +1.0} and the rate problem is essentially solved. We next examine the prospects for detecting this solution to the supernova rate problem. We first study the sources of uncertainty involved in the theoretical estimates of the neutrino detection rate and analyze whether the spectrum of relic neutrinos can be used to independently identify the existence of a supernova rate problem and its source. We consider an ensemble of published and unpublished core collapse supernova simulation models to estimate the uncertainties in the anticipated neutrino luminosities and temperatures. We illustrate how the spectrum of detector events might be used to establish the average

  18. X-ray studies of supernova remnants: a different view of supernova explosions.

    PubMed

    Badenes, Carles

    2010-04-20

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research.

  19. Radio Supernovae: Circum-Stellar Investigation (C.S.I.) of Supernova Progenitor Stars

    DTIC Science & Technology

    2009-02-24

    ar X iv :0 90 2. 40 59 v1 [ as tr o- ph .H E ] 2 4 Fe b 20 09 Radio Supernovae : Circum-Stellar Investigation (C.S.I.) of Supernova Progenitor...FEB 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Radio Supernovae : Circum-Stellar Investigation (C.S.I...of Supernova Progenitor Stars 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f

  20. X-ray studies of supernova remnants: A different view of supernova explosions

    PubMed Central

    Badenes, Carles

    2010-01-01

    The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in