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Sample records for hanni kalju kask

  1. Hanny and the Mystery of the Voorwerp: Citizen Science in the Classroom

    NASA Astrophysics Data System (ADS)

    Costello, K.; Reilly, E.; Bracey, G.; Gay, P.

    2012-08-01

    The highly engaging graphic comic Hanny and the Mystery of the Voorwerp is the focus of an eight-day educational unit geared to middle level students. Activities in the unit link national astronomy standards to the citizen science Zooniverse website through tutorials that lead to analysis of real data online. NASA resources are also included in the unit. The content of the session focused on the terminology and concepts - galaxy formation, types and characteristics of galaxies, use of spectral analysis - needed to classify galaxies. Use of citizen science projects as tools to teach inquiry in the classroom was the primary focus of the workshop. The session included a hands-on experiment taken from the unit, including a NASA spectral analysis activity called "What's the Frequency, Roy G Biv?" In addition, presenters demonstrated the galaxy classification tools found in the "Galaxy Zoo" project at the Zooniverse citizen science website.

  2. News and Views: Double whammy: seeing the Sun and Moon at Glastonbury; What in the world is your object, Hanny? Old Milky Way stars; A star being born; Black hole's big bubble

    NASA Astrophysics Data System (ADS)

    2010-08-01

    Dutch schoolteacher Hanny van Arkel made headlines when she discovered a new type of object, a greenish gas cloud, as part of the Galaxy Zoo project in which citizen scientists can search the Sloan Digital Sky Survey database.

  3. THE HISTORY AND ENVIRONMENT OF A FADED QUASAR: HUBBLE SPACE TELESCOPE OBSERVATIONS OF HANNY'S VOORWERP AND IC 2497

    SciTech Connect

    Keel, William C.; Manning, Anna; Lintott, Chris J.; Schawinski, Kevin; Bennert, Vardha N.; Thomas, Daniel; Chojnowski, S. Drew; Van Arkel, Hanny; Lynn, Stuart

    2012-08-15

    We present Hubble Space Telescope imaging and spectroscopy, along with supporting Galaxy Evolution Explorer and ground-based data, for the extended high-ionization cloud known as Hanny's Voorwerp, near the spiral galaxy IC 2497. Wide Field Camera 3 images show complex dust absorption near the nucleus of IC 2497. The galaxy core in these data is, within the errors, coincident with the very long baseline interferometry core component marking the active nucleus. Space Telescope Imaging Spectrograph (STIS) optical spectra show the active galactic nucleus (AGN) to be a type 2 Seyfert galaxy of rather low luminosity. The derived ionization parameter log U = -3.5 is in accordance with the weak X-ray emission from the AGN. We find no high-ionization gas near the nucleus, adding to the evidence that the AGN is currently at a low radiative output (perhaps with the central black hole having switched to a mode dominated by kinetic energy). The nucleus is accompanied by an expanding ring of ionized gas Almost-Equal-To 500 pc in projected diameter on the side opposite Hanny's Voorwerp. Where sampled by the STIS slit, this ring has Doppler offset Almost-Equal-To 300 km s{sup -1} from the nucleus, implying a kinematic age <7 Multiplication-Sign 10{sup 5} years. Narrowband [O III] and H{alpha}+[N II] Advanced Camera for Surveys images show fine structure in Hanny's Voorwerp, including limb-brightened sections suggesting modest interaction with a galactic outflow and small areas where H{alpha} is strong. We identify these latter regions as regions ionized by recent star formation, in contrast to the AGN ionization of the entire cloud. These candidate 'normal' H II regions contain blue continuum objects, whose colors are consistent with young stellar populations; they appear only in a 2 kpc region toward IC 2497 in projection, perhaps meaning that the star formation was triggered by compression from a narrow outflow. The ionization-sensitive ratio [O III]/H{alpha} shows broad bands

  4. Extended X-ray emission in the IC 2497 - Hanny's Voorwerp system: energy injection in the gas around a fading AGN

    NASA Astrophysics Data System (ADS)

    Sartori, Lia F.; Schawinski, Kevin; Koss, Michael; Treister, Ezequiel; Maksym, W. Peter; Keel, William C.; Urry, C. Megan; Lintott, Chris J.; Wong, O. Ivy

    2016-04-01

    We present deep Chandra X-ray observations of the core of IC 2497, the galaxy associated with Hanny's Voorwerp and hosting a fading AGN. We find extended soft X-ray emission from hot gas around the low intrinsic luminosity (unobscured) AGN (Lbol ˜ 1042-1044 erg s-1). The temperature structure in the hot gas suggests the presence of a bubble or cavity around the fading AGN ({{E}}_bub ˜ 10^{54}{-}10^{55} erg). A possible scenario is that this bubble is inflated by the fading AGN, which after changing accretion state is now in a kinetic mode. Other possibilities are that the bubble has been inflated by the past luminous quasar (Lbol ˜ 1046 erg s-1), or that the temperature gradient is an indication of a shock front from a superwind driven by the AGN. We discuss the possible scenarios and the implications for the AGN-host galaxy interaction, as well as an analogy between AGN and X-ray binaries lifecycles. We conclude that the AGN could inject mechanical energy into the host galaxy at the end of its lifecycle, and thus provide a source for mechanical feedback, in a similar way as observed for X-ray binaries.

  5. SLC5A8-Mediated Switching of STAT3 from a Pro-Oncogenic Signal into a Pro-Apoptotic Signal in Breast Cancer

    DTIC Science & Technology

    2011-06-01

    addition, E2 recruits ER and SIRT1 at the NQO1 (an NRF2 -dependent detoxifying enzyme) promoter to inhibit transcription (25). Since ER and SIRT1...signaling activates the NRF2 pathway in breast cancer. Breast Cancer Res Treat 2010; 124:585-591 26. Laudet V, Hanni C, Coll J, Catzeflis F

  6. Safer Nanomaterials and Nanomanufacturing

    DTIC Science & Technology

    2013-02-01

    Review of Nanotoxicology: Characterization, Dosing and Health Effects . Doody’s Review Service (on-line). 2008. 92. Heideman, C.; Nyugen, N.; Hanni...Force’s need for high performance materials while also addressing its concern for protecting human health and minimizing harm to the environment. 15...11 6. Effect of 1.5 nm TMAT exposure via injection (left panel) or oral exposure (right panel

  7. Homemade Solar Systems

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Through the use of NASA Tech Briefs, Peter Kask, was able to build a solarized domestic hot water system. Also by applying NASA's solar energy design information, he was able to build a swimming pool heating system with minimal outlay for materials.

  8. The Galazy Zoo

    NASA Astrophysics Data System (ADS)

    Schawinski, Kevin

    2016-06-01

    When the Galaxy Zoo website calling for citizen scientists around the world to help classify galaxies from the Sloan Digital Sky Survey was launched, it brought down the servers hosting the images. The Galaxy Zoo tapped into the incredible desire of the public to get involved in and contribute to scientific research. With the he help of over a quarter million citizen scientists, we were able to map out the evolution of galaxy populations from star formation to quiescence and how this "quenching" is related to changes in morphology. Citizen scientists also discovered unusual objects in public data, such as "Hanny's Voorwerp", a quasar light echo which can constrain black hole accretion on timescales of 10-100 kyr. Finally, the work of citizen scientists taking part in Galaxy Zoo points to a future where machine learning and humans both contribute to systems capable of analyzing extremely large data sets.

  9. THE SUDDEN DEATH OF THE NEAREST QUASAR

    SciTech Connect

    Schawinski, Kevin; Virani, Shanil; Megan Urry, C.; Natarajan, Priyamvada; Coppi, Paolo; Evans, Daniel A.; Keel, William C.; Manning, Anna; Lintott, Chris J.; Kaviraj, Sugata; Bamford, Steven P.; Jozsa, Gyula I. G.; Garrett, Michael; Van Arkel, Hanny; Gay, Pamela; Fortson, Lucy

    2010-11-20

    Galaxy formation is significantly modulated by energy output from supermassive black holes at the centers of galaxies which grow in highly efficient luminous quasar phases. The timescale on which black holes transition into and out of such phases is, however, unknown. We present the first measurement of the shutdown timescale for an individual quasar using X-ray observations of the nearby galaxy IC 2497, which hosted a luminous quasar no more than 70,000 years ago that is still seen as a light echo in 'Hanny's Voorwerp', but whose present-day radiative output is lower by at least two, and more likely by over four, orders of magnitude. This extremely rapid shutdown provides new insight into the physics of accretion in supermassive black holes and may signal a transition of the accretion disk to a radiatively inefficient state.

  10. AGN flickering on 10-100 kyr timescales

    NASA Astrophysics Data System (ADS)

    Sartori, Lia F.; Schawinski, Kevin; Kill, Bill; Maksym, Peter; Koss, Michael; Argo, Megan; Urry, Meg; Wong, Ivy; Lintott, Chris

    2016-08-01

    The study of AGN variability on timescales of 10^4-10^5 years is important in order to understand the BH - host galaxy interaction and coevolution. The discovery of "Hanny's Voorwerp" (HV), an extended emission line region associated with the nearby galaxy IC 2497, provided us with a laboratory to study AGN variability over such timescales. HV was illuminated by a strong quasar in IC 2497, but this quasar significantly shut down in the last 200 kyrs. Thanks to its recent shutdown we can now explore the host galaxy unimpeded by the presence of a quasar dominating the observations, while the Voorwerp preserves the echoes of its past activity. Recent studies on the optical properties of hard X-ray selected AGN suggest that AGN may flicker on and off hundreds or thousands times with each burst lasting ~10^5 yrs. Systems similar to IC 2497 and HV, the so-called Voorwerpjes, allow us to constrain the last stages of the AGN lifecycle. On the other hand, we recently suggested that the switch on phase may be observed in the so-called optically elusive AGN. In this talk I will review both observational evidence and results from simulation work which support this picture, and explain how optically elusive AGN and Voorwerpjes galaxies can help us to understand different phases of the AGN lifecycle. Moreover, I will discuss possible implications for AGN feedback, BH - host galaxy coevolution, and the analogy between AGN and X-ray binaries accretion physics.

  11. General relativistic radiative transfer code in rotating black hole space-time: ARTIST

    NASA Astrophysics Data System (ADS)

    Takahashi, Rohta; Umemura, Masayuki

    2017-02-01

    We present a general relativistic radiative transfer code, ARTIST (Authentic Radiative Transfer In Space-Time), that is a perfectly causal scheme to pursue the propagation of radiation with absorption and scattering around a Kerr black hole. The code explicitly solves the invariant radiation intensity along null geodesics in the Kerr-Schild coordinates, and therefore properly includes light bending, Doppler boosting, frame dragging, and gravitational redshifts. The notable aspect of ARTIST is that it conserves the radiative energy with high accuracy, and is not subject to the numerical diffusion, since the transfer is solved on long characteristics along null geodesics. We first solve the wavefront propagation around a Kerr black hole that was originally explored by Hanni. This demonstrates repeated wavefront collisions, light bending, and causal propagation of radiation with the speed of light. We show that the decay rate of the total energy of wavefronts near a black hole is determined solely by the black hole spin in late phases, in agreement with analytic expectations. As a result, the ARTIST turns out to correctly solve the general relativistic radiation fields until late phases as t ˜ 90 M. We also explore the effects of absorption and scattering, and apply this code for a photon wall problem and an orbiting hotspot problem. All the simulations in this study are performed in the equatorial plane around a Kerr black hole. The ARTIST is the first step to realize the general relativistic radiation hydrodynamics.

  12. MUSE Reveals a Recent Merger in the Post-starburst Host Galaxy of the TDE ASASSN-14li

    NASA Astrophysics Data System (ADS)

    Prieto, J. L.; Krühler, T.; Anderson, J. P.; Galbany, L.; Kochanek, C. S.; Aquino, E.; Brown, J. S.; Dong, Subo; Förster, F.; Holoien, T. W.-S.; Kuncarayakti, H.; Maureira, J. C.; Rosales-Ortega, F. F.; Sánchez, S. F.; Shappee, B. J.; Stanek, K. Z.

    2016-10-01

    We present Multi Unit Spectroscopic Explorer (MUSE) integral field spectroscopic observations of the host galaxy (PGC 043234) of one of the closest (z = 0.0206, D ≃ 90 Mpc) and best-studied tidal disruption events (TDEs), ASASSN-14li. The MUSE integral field data reveal asymmetric and filamentary structures that extend up to ≳10 kpc from the post-starburst host galaxy of ASASSN-14li. The structures are traced only through the strong nebular [O iii] λ5007, [N ii] λ6584, and Hα emission lines. The total off-nuclear [O iii] λ5007 luminosity is 4.7 × 1039 erg s-1, and the ionized H mass is ˜ {10}4(500/{n}{{e}}) {M}⊙ . Based on the Baldwin-Phillips-Terlevich diagram, the nebular emission can be driven by either AGN photoionization or shock excitation, with AGN photoionization favored given the narrow intrinsic line widths. The emission line ratios and spatial distribution strongly resemble ionization nebulae around fading AGNs such as IC 2497 (Hanny's Voorwerp) and ionization “cones” around Seyfert 2 nuclei. The morphology of the emission line filaments strongly suggest that PGC 043234 is a recent merger, which likely triggered a strong starburst and AGN activity leading to the post-starburst spectral signatures and the extended nebular emission line features we see today. We briefly discuss the implications of these observations in the context of the strongly enhanced TDE rates observed in post-starburst galaxies and their connection to enhanced theoretical TDE rates produced by supermassive black hole binaries.

  13. Spatially resolved spectra of the 'teacup' active galactic nucleus: tracing the history of a dying quasar

    SciTech Connect

    Gagne, J. P.; Crenshaw, D. M.; Fischer, T. C.; Kraemer, S. B.; Schmitt, H. R.; Keel, W. C.; Rafter, S.; Bennert, V. N.; Schawinski, K.

    2014-09-01

    The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing extended emission-line regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup active galactic nucleus (AGN). Nicknamed for its EELR, which has a 'handle'-like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze the physical conditions of this galaxy with long-slit, ground-based spectroscopy from the Lowell, Lick, and KPNO observatories. With the Lowell 1.8 m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] λ6716/λ6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by this amount in a continuous fashion over 46,000 yr, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long timescale variability.

  14. Karyotypic similarities between two species of Rhamphichthys (Rhamphichthyidae, Gymnotiformes) from the Amazon basin.

    PubMed

    da Silva, Patrícia Corrêa; Nagamachi, Cleusa Yoshiko; Silva, Danillo Dos Santos; Milhomem, Susana Suely Rodrigues; Cardoso, Adauto Lima; de Oliveira, Jonas Alves; Pieczarka, Julio Cesar

    2013-10-24

    The family Rhamphichthyidae includes three genera: Rhamphichthys Müller et Troschel, 1846, Gymnorhamphichthys M. M. Ellis, 1912 and Iracema Triques, 1996. From this family, only the species Rhamphichthys hanni Meinken, 1937 has had its karyotype described. Here, we describe the karyotypes of two additional Rhamphichthys species: Rhamphichthys marmoratus Castelnau, 1855 from the Reserva de Desenvolvimento Sustentável Mamirauá, Amazonas state and Rhamphichthys prope rostratus Linnaeus, 1766 from Pará state, both in Brazil. Our karyotypic analyses demonstrated that the diploid number is conserved for the genus (2n = 50), but the karyotypic formulas (KFs) differed between Rhamphichthys marmoratus (44m/sm+6a) and Rhamphichthys prope rostratus (42m/sm+8a). In both species, the constitutive heterochromatin (CH) was located in the centromeric region of most chromosomes. Large heterochromatic blocks were found on the long arms of pairs 4 and 14 in Rhamphichthys marmoratus and on chromosomes 3, 4 and 19 in Rhamphichthys prope rostratus, which also has a heteromorphism in chromosome pair 1. The CH was DAPI positive, indicating that it is rich in AT base pairs. The Nucleolus Organizer Region (NOR) showed staining at a single location in both species: the long arm of pair 1 in Rhamphichthys marmoratus and the long arm of pair 12 in Rhamphichthys prope rostratus, where it showed a size heteromorphism. CMA3 staining coincided with that of Ag-NOR, indicating that the ribosomal genes contain interspaced GC-rich sequences. FISH with an 18S rDNA probe confirmed that there is only one NOR site in each species. These results can be used as potential cytogenetic markers for fish populations, and comparative analysis of the karyotypes of Hypopygus Hoedman, 1962, Rhamphichthys and Steatogenys Boulenger, 1898 suggests that the first two genera diverged later that the third.

  15. Karyotypic similarities between two species of Rhamphichthys (Rhamphichthyidae, Gymnotiformes) from the Amazon basin

    PubMed Central

    da Silva, Patrícia Corrêa; Nagamachi, Cleusa Yoshiko; Silva, Danillo dos Santos; Milhomem, Susana Suely Rodrigues; Cardoso, Adauto Lima; de Oliveira, Jonas Alves; Pieczarka, Julio Cesar

    2013-01-01

    Abstract The family Rhamphichthyidae includes three genera: Rhamphichthys Müller et Troschel, 1846, Gymnorhamphichthys M. M. Ellis, 1912 and Iracema Triques, 1996. From this family, only the species Rhamphichthys hanni Meinken, 1937 has had its karyotype described. Here, we describe the karyotypes of two additional Rhamphichthys species: Rhamphichthys marmoratus Castelnau, 1855 from the Reserva de Desenvolvimento Sustentável Mamirauá, Amazonas state and Rhamphichthys prope rostratus Linnaeus, 1766 from Pará state, both in Brazil. Our karyotypic analyses demonstrated that the diploid number is conserved for the genus (2n = 50), but the karyotypic formulas (KFs) differed between Rhamphichthys marmoratus (44m/sm+6a) and Rhamphichthys prope rostratus (42m/sm+8a). In both species, the constitutive heterochromatin (CH) was located in the centromeric region of most chromosomes. Large heterochromatic blocks were found on the long arms of pairs 4 and 14 in Rhamphichthys marmoratus and on chromosomes 3, 4 and 19 in Rhamphichthys prope rostratus, which also has a heteromorphism in chromosome pair 1. The CH was DAPI positive, indicating that it is rich in AT base pairs. The Nucleolus Organizer Region (NOR) showed staining at a single location in both species: the long arm of pair 1 in Rhamphichthys marmoratus and the long arm of pair 12 in Rhamphichthys prope rostratus, where it showed a size heteromorphism. CMA3 staining coincided with that of Ag-NOR, indicating that the ribosomal genes contain interspaced GC-rich sequences. FISH with an 18S rDNA probe confirmed that there is only one NOR site in each species. These results can be used as potential cytogenetic markers for fish populations, and comparative analysis of the karyotypes of Hypopygus Hoedman, 1962, Rhamphichthys and Steatogenys Boulenger, 1898 suggests that the first two genera diverged later that the third. PMID:24455102

  16. THE [O III] NEBULA OF THE MERGER REMNANT NGC 7252: A LIKELY FAINT IONIZATION ECHO

    SciTech Connect

    Schweizer, Francois; Kelson, Daniel D.; Villanueva, Edward V.; Seitzer, Patrick; Walth, Gregory L.

    2013-08-20

    We present images and spectra of a {approx}10 kpc-sized emission-line nebulosity discovered in the prototypical merger remnant NGC 7252 and dubbed the ''[O III] nebula'' because of its dominant [O III] {lambda}5007 line. This nebula seems to yield the first sign of episodic active galactic nucleus (AGN) activity still occurring in the remnant, {approx}220 Myr after the coalescence of two gas-rich galaxies. Its location and kinematics suggest it belongs to a stream of tidal-tail gas falling back into the remnant. Its integrated [O III] {lambda}5007 luminosity is 1.4 Multiplication-Sign 10{sup 40} erg s{sup -1}, and its spectrum features some high-excitation lines, including He II {lambda}4686. In diagnostic line-ratio diagrams, the nebula lies in the domain of Seyfert galaxies, suggesting that it is photoionized by a source with a power-law spectrum. Yet, a search for AGN activity in NGC 7252 from X-rays to radio wavelengths yields no detection, with the most stringent upper limit set by X-ray observations. The upper luminosity limit of L{sub 2-10{sub keV,0}}<5 Multiplication-Sign 10{sup 39} erg s{sup -1} estimated for the nucleus is {approx}10{sup 3} times lower than the minimum ionizing luminosity of {approx}> 5 Multiplication-Sign 10{sup 42} erg s{sup -1} necessary to excite the nebula. This large discrepancy suggests that the nebula is a faint ionization echo excited by a mildly active nucleus that has declined by {approx}3 orders of magnitude over the past 20,000-200,000 yr. In many ways this nebula resembles the prototypical ''Hanny's Voorwerp'' near IC 2497, but its size is 3 Multiplication-Sign smaller and its [O III] luminosity {approx}100 Multiplication-Sign lower. We propose that it be classified as an extended emission-line region (EELR). The [O III] nebula is then the lowest-luminosity ionization echo and EELR discovered so far, indicative of recent, probably sputtering AGN activity of Seyfert-like intensity in NGC 7252.

  17. Tracking Galaxy Evolution Through Low-Frequency Radio Continuum Observations using SKA and Citizen-Science Research using Multi-Wavelength Data

    NASA Astrophysics Data System (ADS)

    Hota, Ananda; Konar, C.; Stalin, C. S.; Vaddi, Sravani; Mohanty, Pradeepta K.; Dabhade, Pratik; Dharmik Bhoga, Sai Arun; Rajoria, Megha; Sethi, Sagar

    2016-12-01

    We present a brief review of progress in the understanding of general spiral and elliptical galaxies, through merger, star formation and AGN activities. With reference to case studies performed with the GMRT, we highlight the unique aspects of studying galaxies in the radio wavelengths where powerful quasars and bright radio galaxies are traditionally the dominating subjects. Though AGN or quasar activity is extremely energetic, it is extremely short-lived. This justify focussing on transitional galaxies to find relic-evidences of the immediate past AGN-feedback which decide the future course of evolution of a galaxy. Relic radio lobes can be best detected in low frequency observations with the GMRT, LOFAR and in future SKA. The age of these relic radio plasma can be as old as a few hundred Myr. There is a huge gap between this and what is found in optical bands. The very first relic-evidences of a past quasar activity (Hanny's Voorwerp) was discovered in 2007 by a Galaxy Zoo citizen-scientist, a school teacher, in the optical bands. This relic is around a few tens of thousand years old. More discoveries needed to match these time-scales with star formation time-scales in AGN host galaxies to better understand black hole galaxy co-evolution process via feedback-driven quenching of star formation. It is now well-accepted that discovery and characterization of such faint fuzzy relic features can be more efficiently done by human eye than a machine. Radio interferometry images are more complicated than optical and need the citizen-scientists to be trained. RAD@home, the only Indian citizen-science research project in astronomy, analysing TIFR GMRT Sky Survey (TGSS) 150 MHz data and observing from the Giant Meterwave Radio Telescope (GMRT), was launched in April 2013. Unique, zero-infrastructure zero-funded design of RAD@home as a collaboratory of 69 trained e-astronomers is briefly described. Some of the new-found objects like episodic radio galaxies, radio-jet and

  18. AAS 228: Day 2 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    Editors Note:This week were at the 228th AAS Meeting in San Diego, CA. Along with a team ofauthors from astrobites.com, I will bewritingupdates on selectedevents at themeeting and posting twiceeach day. Follow along here or atastrobites.com, or catch ourlive-tweeted updates from the@astrobites Twitter account. The usual posting schedule for AAS Nova will resumenext week.Plenary Session (Day 1) The Galaxy Zoo(by Benny Tsang)Galaxy Zoo was so hot that the servers hosting the galaxy images got melted down soon after being launched.Kevin Schawinski from ETH Zurich took us on a tour ofhis wonderful Galaxy Zoo. It is a huge zoo with about a quarter million zookeepers, they are citizen astronomers who collaboratively classify galaxies by their looks as an attempt to understand galaxy evolution. The big question that is being answered is: how do blue, actively star-forming galaxies evolve into red, quiescent (non-star-forming) galaxies? The Zoo helped reveal that blue galaxies turn into red galaxies via two possible paths galaxies might run out of supply of gas and shut off star formation slowly; or they could merge with one another and turn off star formation by destroying the gas reservoir rapidly!The Galaxy Zoo project also led to the discoveries of:Green Peas: they are the living fossils of galaxy evolution; compact, bright, green galaxies that are actively forming starsOverlapping galaxies: they are pairs of galaxies that are separated physically but happen to lie on the same line of sight; they provide excellent laboratories for studying dust extinctionHannys Voorwerp: an unusual object named after Hanny the discoverer, which is believed to be the first detection of quasar light echoThe idea of Galaxy Zoo in getting help from citizen scientists was further extended into an award-winningproject known as the Zooniverse, which is an online platform for streamlined crowd-sourcing for scientific research that requires human input. The future of astronomy is going to be