Eight Ultra-Faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey

Drlica-Wagner, A.; Bechtol, K.; Rykoff, E. S.; Luque, E.; Queiroz, Anna Bárbara de Andrade; Mao, Yao-Yuan; Wechsler, Risa H.; Simon, J. D.; Santiago, B.; Yanny, B.; Balbinot, E.; Dodelson, Scott; Neto, A. Fausti; James, D. J.; Li, T. S.; Maia, M. A. G.; Marshall, J. L.; Pieres, A.; Stringer, K. M.; Walker, A. R.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Costa, L. N. da; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, Joshua A.; Gaztañaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutiérrez, G.; Honscheid, K.; Kuêhn, K.; Kuropatkin, N.; Lahav, O.; Martini, Paul; Miquel, R.; Nord, B.; Ogando, R. L. C.; Plazas, A. A.; Reil, K.; Roodman, A.; Šako, M.; Sánchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarlè, G.; Tucker, D. L.; Vikram, V.; Wester, W. C.; Zhang, Y.; Zuntz, J.

doi:10.1088/0004-637x/813/2/109

Cited by 497 publications

(518 citation statements)

References 113 publications

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“…The black line gives the result for the 11 classical satellites of the Milky Way, and the black dot is the estimation of Koposov et al (2008), which is based on the estimate of 45 MW satellites with MV < −5 and r < 280kpc from SDSS DR5. Recently more stellites of MW have been discovered by the Dark Energy Survey (DES; Bechtol et al 2015;Drlica-Wagner et al 2015;Koposov et al 2015), the VST-Atlas (Torrealba et al 2016) and Pan-STARRS 3π surveys (Laevens et al 2015a,b). Fig.11 of Bose et al (2017) has included these latest observed satellites, which is consistent with the data shown in our Fig.…”

Section: The Abundance Of Milky Way Satellitesmentioning

confidence: 99%

The galaxy population in cold and warm dark matter cosmologies

Wang

González-Pérez²,

Xie

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We use a pair of high resolution N-body simulations implementing two dark matter models, namely the standard cold dark matter (CDM) cosmogony and a warm dark matter (WDM) alternative where the dark matter particle is a 1.5 keV thermal relic. We combine these simulations with the GALFORM semi-analytical galaxy formation model in order to explore differences between the resulting galaxy populations. We use GALFORM model variants for CDM and WDM that result in the same z = 0 galaxy stellar mass function by construction. We find that most of the studied galaxy properties have the same values in these two models, indicating that both dark matter scenarios match current observational data equally well. Even in under-dense regions, where discrepancies in structure formation between CDM and WDM are expected to be most pronounced, the galaxy properties are only slightly different. The only significant difference in the local universe we find is in the galaxy populations of "Local Volumes", regions of radius 1 to 8Mpc around simulated Milky Way analogues. In such regions our WDM model provides a better match to observed local galaxy number counts and is five times more likely than the CDM model to predict subregions within them that are as empty as the observed Local Void. Thus, a highly complete census of the Local Volume and future surveys of void regions could provide constraints on the nature of dark matter.

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Section: The Abundance Of Milky Way Satellitesmentioning

confidence: 99%

The galaxy population in cold and warm dark matter cosmologies

Wang

González-Pérez²,

Xie

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…The Dark Energy Survey (DES) recently reported the discovery of new ultra-faint dwarf galaxies (Bechtol et al 2015;Koposov et al 2015;Drlica-Wagner et al 2015;Jethwa et al 2016). We can consider their contribution to the observed luminosity function following the analysis by Jethwa et al (2016) who find that 12 of the 14 satellites have > 50% probability of having been brought in as satellites of the LMC itself (at 95% confidence).…”

Section: Satellites Of the Milky Waymentioning

confidence: 99%

Reionization in sterile neutrino cosmologies

Bose¹,

Frenk²,

Hou³

et al. 2016

Mon. Not. R. Astron. Soc.

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe investigate the process of reionisation in a model in which the dark matter is a warm elementary particle such as a sterile neutrino. We focus on models that are consistent with the dark matter decay interpretation of the recently detected line at 3.5 keV in the X-ray spectra of galaxies and clusters. In warm dark matter models the primordial spectrum of density perturbations has a cut-off on the scale of dwarf galaxies. Structure formation therefore begins later than in the standard cold dark matter (CDM) model and very few objects form below the cut-off mass scale. To calculate the number of ionising photons, we use the Durham semianalytic model of galaxy formation, GALFORM. We find that even the most extreme 7 keV sterile neutrino we consider is able to reionise the Universe early enough to be compatible with the bounds on the epoch of reionisation from Planck. This, perhaps surprising, result arises from the rapid build-up of high redshift galaxies in the sterile neutrino models which is also reflected in a faster evolution of their far-UV luminosity function between 10 > z > 7 than in CDM. The dominant sources of ionising photons are systematically more massive in the sterile neutrino models than in CDM. As a consistency check on the models, we calculate the present-day luminosity function of satellites of Milky Way-like galaxies. When the satellites recently discovered in the DES survey are taken into account, strong constraints are placed on viable sterile neutrino models.

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“…Despite the mission's focus on cosmology, DES data have already produced a wealth of results pertaining to resolved stellar populations in the Galaxy and its vicinity, including the analysis of the structure and stellar populations in the outskirts of the Large Magellanic Cloud (LMC; Balbinot et al 2015), the identification of new Galactic companions Drlica-Wagner et al 2015;Kim & Jerjen 2015;Koposov et al 2015;Luque et al 2016), and the development of a new search for variable stars exclusively based on DES data (D. Hatt et al 2016, in preparation).…”

Section: Introductionmentioning

confidence: 99%

The Phoenix Stream: A Cold Stream in the Southern Hemisphere

Balbinot¹,

Yanny²,

Li³

et al. 2016

ApJ

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We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age τ=11.5±0.5 Gyr and [Fe/H]<−1.6, located 17.5±0.9 kpc from the Sun, gives an adequate description of the stream stellar population. The stream is detected over an extension of 8°.1 (2.5 kpc) and has a width of ∼54 pc assuming a Gaussian profile, indicating that a globular cluster (GC) is a probable progenitor. There is no known GC within 5 kpc that is compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities (ODs) along the stream, however, no obvious counterpart-bound stellar system is visible in the coadded images. We also find ODs along the stream that appear to be symmetrically distributed-consistent with the epicyclic OD scenario for the formation of cold streams-as well as a misalignment between the northern and southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe OD.

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Eight Ultra-Faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey

Cited by 497 publications

References 113 publications

The galaxy population in cold and warm dark matter cosmologies

The galaxy population in cold and warm dark matter cosmologies

Reionization in sterile neutrino cosmologies

The Phoenix Stream: A Cold Stream in the Southern Hemisphere

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