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Related papers: Charting Unexplored Dwarf Galaxy Territory With RR…

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The number and distribution of dwarf satellite galaxies remain a critical test of cold dark matter-dominated structure formation on small scales. Until recently, observational information about galaxy formation on these scales has been…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Ryan Speller , James E. Taylor

We present results for the QUEST RR Lyrae Survey at low galactic latitude, conducted entirely with observations obtained with the QUEST mosaic camera and the 1.0/1.5m J\"urgen Stock Schmidt telescope at the National Observatory of…

Astrophysics of Galaxies · Physics 2015-06-11 Cecilia Mateu , A. Katherina Vivas , Juan José Downes , César Briceño , Robert Zinn , Gustavo Cruz-Diaz

We propose that luminous transients, including novae and supernovae, can be used to detect the faintest galaxies in the universe. Beyond a few Mpc, dwarf galaxies with stellar masses $<10^6 M_{\odot}$ will likely be too faint and/or too low…

Astrophysics of Galaxies · Physics 2015-05-27 Charlie Conroy , James S. Bullock

RR Lyr stars are ideal massless tracers that can be used to study the total mass and dark matter content of the outer halo of the Milky Way. This is because they are easy to find in the light curve databases of large stellar surveys and…

We present new metallicity measurements for 298 individual red giant branch stars in eight of the least luminous dwarf spheroidal galaxies (dSphs) in the Milky Way (MW) system. Our technique is based on medium resolution Keck/DEIMOS…

Astrophysics · Physics 2010-10-28 Evan N. Kirby , Joshua D. Simon , Marla Geha , Puragra Guhathakurta , Anna Frebel

(Abridged) The Sloan Digital Sky Survey now extends over a large enough region that galaxies in low density environments can be detected. Rojas et al. have developed a technique to extract more than 1000 void galaxies with delta rho/rho <…

Astrophysics · Physics 2009-11-10 Fiona Hoyle , Randall R. Rojas , Michael S. Vogeley , John Brinkmann

Dwarf satellite galaxies are a key probe of dark matter and of galaxy formation on small scales and of the dark matter halo masses of their central galaxies. They have very low surface brightness, which makes it difficult to identify and…

Astrophysics of Galaxies · Physics 2014-06-11 Allison Merritt , Pieter van Dokkum , Roberto Abraham

We present a kinematical study of the outer halo (r_GC approximately 60 to 160 kpc) of the Milky Way based on spectroscopy of 55 RR Lyrae stars obtained with the ESI instrument on the Keck II telescope. Our spectroscopic targets were…

We review evidence that the census of Milky Way satellites similar to those known may be incomplete at low latitude due to obscuration and in the outer halo due to a decreasing sensitivity to dwarf satellites with distance. We evaluate the…

Astrophysics · Physics 2008-11-26 B. Willman , F. Governato , J. J. Dalcanton , D. Reed , T. Quinn

Because of strong and spatially highly variable interstellar extinction and extreme source crowding, the faint (K>15) stellar population in the Milky Way's nuclear cluster is still poorly studied. RR Lyrae stars provide us with a tool to…

Most of known RR Lyraes are type ab RR Lyraes (RRLab), and they are the excellent tool to map the Milky Way and its substructures. We find that 1148 RRLab stars determined by Drake et al.(2013) have been observed by spectroscopic surveys of…

Astrophysics of Galaxies · Physics 2018-03-28 Iminhaji Ablimit , Gang Zhao

RR Lyrae stars (RRLs) are tracers of the Milky Way's fossil record, holding valuable information on its formation and early evolution. Owing to the high interstellar extinction endemic to the Galactic plane, distant RRLs lying at low…

Among the most stringent constraints on the dark matter annihilation cross section are those derived from observations of dwarf galaxies by the Fermi Gamma-Ray Space Telescope. As current (e.g., Dark Energy Survey, DES) and future (Large…

High Energy Astrophysical Phenomena · Physics 2015-03-18 Chen He , Keith Bechtol , Andrew P. Hearin , Dan Hooper

Although it a very narrow angle survey, the depth of the HDF results in its sampling a significant volume of the halo of our galaxy. Thus it is useful for the purposes of detecting (or placing upper limits on the distribution of)…

Astrophysics · Physics 2007-05-23 Steven D. Kawaler

We have obtained deep Hubble Space Telescope (HST) imaging of four faint and ultra-faint dwarf galaxy candidates in the vicinity of M101 - Dw21, Dw22, Dw23 and Dw35, originally discovered by Bennet et al. (2017). Previous distance estimates…

Astrophysics of Galaxies · Physics 2020-04-15 P. Bennet , D. J. Sand , D. Crnojevic , K. Spekkens , A. Karunakaran , D. Zaritsky , B. Mutlu-Pakdil

A search for RR Lyrae stars (RRLS) in 840 sq.deg. of the sky in right ascension 150 - 210 deg and declination -10 - +10 deg yielded 1013 type ab and 359 type c RRLS. This sample is used to study the density profile of the Galactic halo,…

Astrophysics of Galaxies · Physics 2015-06-18 R. Zinn , B. Horowitz , A. K. Vivas , C. Baltay , N. Ellman , E. Hadjiyska , D. Rabinowitz , L. Miller

According to the Cold Dark Matter (CDM) hierarchical clustering theory of galaxy and large scale structure formation, there should be numerous low mass dark matter haloes present in the Universe today. If these haloes contain sufficient…

Astrophysics · Physics 2009-11-10 S. Roberts , J. Davies , S. Sabatini , W. van Driel , K. O'Neil , M. Baes , S. Linder , R. Smith , Rh. Evans

We present an extensive search for RR Lyrae stars in and around the ultra-faint Milky Way companions Segue 2 and Segue 3. The former (M_V = -2.5, Belokurov et al. 2009) appears to be an extremely faint dwarf galaxy companion of the Milky…