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Dwarf galaxy
About: Dwarf galaxy is a research topic. Over the lifetime, 11785 publications have been published within this topic receiving 486050 citations.
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TL;DR: In this paper, the relation between stellar mass and gas-phase metallicity was studied using the Sloan Digital Sky Survey imaging and spectroscopy of ~53,000 star-forming galaxies at z = 0.1.
Abstract: We utilize Sloan Digital Sky Survey imaging and spectroscopy of ~53,000 star-forming galaxies at z ~ 0.1 to study the relation between stellar mass and gas-phase metallicity. We derive gas-phase oxygen abundances and stellar masses using new techniques that make use of the latest stellar evolutionary synthesis and photoionization models. We find a tight (?0.1 dex) correlation between stellar mass and metallicity spanning over 3 orders of magnitude in stellar mass and a factor of 10 in metallicity. The relation is relatively steep from 108.5 to 1010.5 M? h, in good accord with known trends between luminosity and metallicity, but flattens above 1010.5 M?. We use indirect estimates of the gas mass based on the H? luminosity to compare our data to predictions from simple closed box chemical evolution models. We show that metal loss is strongly anticorrelated with baryonic mass, with low-mass dwarf galaxies being 5 times more metal depleted than L* galaxies at z ~ 0.1. Evidence for metal depletion is not confined to dwarf galaxies but is found in galaxies with masses as high as 1010 M?. We interpret this as strong evidence of both the ubiquity of galactic winds and their effectiveness in removing metals from galaxy potential wells.
3,621 citations
TL;DR: In this article, the relation between stellar mass and gas-phase metallicity was studied using the Sloan Digital Sky Survey imaging and spectroscopy of ~53,000 star-forming galaxies at z~0.1.
Abstract: We utilize Sloan Digital Sky Survey imaging and spectroscopy of ~53,000 star-forming galaxies at z~0.1 to study the relation between stellar mass and gas-phase metallicity. We derive gas-phase oxygen abundances and stellar masses using new techniques which make use of the latest stellar evolutionary synthesis and photoionization models. We find a tight (+/-0.1 dex) correlation between stellar mass and metallicity spanning over 3 orders of magnitude in stellar mass and a factor of 10 in metallicity. The relation is relatively steep from 10^{8.5} - 10^{10.5} M_sun, in good accord with known trends between luminosity and metallicity, but flattens above 10^{10.5} M_sun. We use indirect estimates of the gas mass based on the H-alpha luminosity to compare our data to predictions from simple closed box chemical evolution models. We show that metal loss is strongly anti-correlated with baryonic mass, with low mass dwarf galaxies being 5 times more metal-depleted than L* galaxies at z~0.1. Evidence for metal depletion is not confined to dwarf galaxies, but is found in galaxies with masses as high as 10^{10} M_sun. We interpret this as strong evidence both of the ubiquity of galactic winds and of their effectiveness in removing metals from galaxy potential wells.
3,276 citations
TL;DR: In this paper, the authors compare the observed and predicted VDFs cross at B50 km s~1, indicating that the predicted abundance of satellites with km s-1 V circ Z 50 is in reasonably good agreement with observations.
Abstract: According to the hierarchical clustering scenario, galaxies are assembled by merging and accretion of numerous satellites of di†erent sizes and masses. This ongoing process is not 100% efficient in destroying all of the accreted satellites, as evidenced by the satellites of our Galaxy and of M31. Using published data, we have compiled the circular velocity distribution function (VDF) of galaxy satellites in the (V circ ) Local Group. We Ðnd that within the volumes of radius of 570 kpc (400 h~1 kpc assuming the Hubble constant1 h \ 0.7) centered on the Milky Way and Andromeda, the average VDF is roughly approx- imated as km s~1)~1.4B0.4 h3 Mpc~3 for in the range B10E70 km s~1. n( ( V circ ) B 55 ^ 11(V circ /10 V circ The observed VDF is compared with results of high-resolution cosmological simulations. We Ðnd that the VDF in models is very di†erent from the observed one : km s~1)~2.75 h3 n( ( V circ ) B 1200(V circ /10 Mpc~3. Cosmological models thus predict that a halo the size of our Galaxy should have about 50 dark matter satellites with circular velocity greater than 20 km s~1 and mass greater than 3 ) 108 within M _ a 570 kpc radius. This number is signiÐcantly higher than the approximately dozen satellites actually observed around our Galaxy. The di†erence is even larger if we consider the abundance of satellites in simulated galaxy groups similar to the Local Group. The models predict D300 satellites inside a 1.5 Mpc radius, while only D40 satellites are observed in the Local Group. The observed and predicted VDFs cross at B50 km s~1, indicating that the predicted abundance of satellites with km s~1 V circ Z 50 is in reasonably good agreement with observations. We conclude, therefore, that unless a large fraction of the Local Group satellites has been missed in observations, there is a dramatic discrepancy between observations and hierarchical models, regardless of the model parameters. We discuss several possible explanations for this discrepancy including identiÐcation of some satellites with the high-velocity clouds observed in the Local Group and the existence of dark satellites that failed to accrete gas and form stars either because of the expulsion of gas in the supernovae-driven winds or because of gas heating by the intergalactic ionizing background. Subject headings : cosmology : theory E galaxies : clusters : general E galaxies : interactions E Galaxy : formation E Local Group E methods : numerical
2,864 citations
TL;DR: The Virgo Consortium's EAGLE project as discussed by the authors is a suite of hydrodynamical simulations that follow the formation of galaxies and black holes in representative volumes, where thermal energy is injected into the gas, allowing winds to develop without predetermined speed or mass loading factors.
Abstract: We introduce the Virgo Consortium's EAGLE project, a suite of hydrodynamical simulations that follow the formation of galaxies and black holes in representative volumes. We discuss the limitations of such simulations in light of their finite resolution and poorly constrained subgrid physics, and how these affect their predictive power. One major improvement is our treatment of feedback from massive stars and AGN in which thermal energy is injected into the gas without the need to turn off cooling or hydrodynamical forces, allowing winds to develop without predetermined speed or mass loading factors. Because the feedback efficiencies cannot be predicted from first principles, we calibrate them to the z~0 galaxy stellar mass function and the amplitude of the galaxy-central black hole mass relation, also taking galaxy sizes into account. The observed galaxy mass function is reproduced to ≲0.2 dex over the full mass range, 108
2,828 citations
TL;DR: The Local Group dwarfs offer a unique window to the detailed properties of the most common type of galaxy in the Universe as mentioned in this paper. But, the local group dwarfs are not suitable for direct observation.
Abstract: ▪ Abstract The Local Group dwarf galaxies offer a unique window to the detailed properties of the most common type of galaxy in the Universe. In this review, I update the census of Local Group dwarfs based on the most recent distance and radial velocity determinations. I then discuss the detailed properties of this sample, including (a) the integrated photometric parameters and optical structures of these galaxies, (b) the content, nature, and distribution of their interstellar medium (ISM), (c) their heavy-element abundances derived from both stars and nebulae, (d) the complex and varied star-formation histories of these dwarfs, (e) their internal kinematics, stressing the relevance of these galaxies to the “dark matter problem” and to alternative interpretations, and (f) evidence for past, ongoing, and future interactions of these dwarfs with other galaxies in the Local Group and beyond. To complement the discussion and to serve as a foundation for future work, I present an extensive set of basic observ...
2,448 citations