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Title: Faint dwarfs in nearby groups

Abstract

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 limited mainly to the Local Group. We have searched for faint analogues of Local Group dwarfs around nearby bright galaxies, using a spatial clustering analysis of the photometric catalog of the Sloan Digital Sky Survey (SDSS) Data Release 8. Several other recent searches of SDSS have detected clustered satellite populations down to Δm{sub r} ≡ (m{sub r,} {sub sat} – m{sub r,} {sub main}) ∼ 6-8, using photometric redshifts to reduce background contamination. SDSS photometric redshifts are relatively imprecise, however, for faint and nearby galaxies. Instead, we use angular size to select potential nearby dwarfs and consider only the nearest isolated bright galaxies as primaries. As a result, we are able to detect an excess clustering signal from companions down to Δm{sub r} = 12, 4 mag fainter than most recent studies. We detect an overdensity of objects at separations <400 kpc, corresponding to about 4.6 ± 0.5 satellites per central galaxy, consistent with the satellite abundance expected from the Local Group, given our selection function. Althoughmore » the sample of satellites detected is incomplete by construction, since it excludes the least and most compact dwarfs, this detection provides a lower bound on the average satellite luminosity function, down to luminosities corresponding to the faintest ''classical'' dwarfs of the Local Group.« less

Authors:
Publication Date:
OSTI Identifier:
22356544
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 788; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CATALOGS; CONSTRUCTION; DISTRIBUTION; GALAXIES; LUMINOSITY; MASS; NONLUMINOUS MATTER; RED SHIFT; SATELLITES

Citation Formats

Speller, Ryan, and Taylor, James E., E-mail: rspeller@uwaterloo.ca, E-mail: taylor@uwaterloo.ca. Faint dwarfs in nearby groups. United States: N. p., 2014. Web. doi:10.1088/0004-637X/788/2/188.
Speller, Ryan, & Taylor, James E., E-mail: rspeller@uwaterloo.ca, E-mail: taylor@uwaterloo.ca. Faint dwarfs in nearby groups. United States. https://doi.org/10.1088/0004-637X/788/2/188
Speller, Ryan, and Taylor, James E., E-mail: rspeller@uwaterloo.ca, E-mail: taylor@uwaterloo.ca. 2014. "Faint dwarfs in nearby groups". United States. https://doi.org/10.1088/0004-637X/788/2/188.
@article{osti_22356544,
title = {Faint dwarfs in nearby groups},
author = {Speller, Ryan and Taylor, James E., E-mail: rspeller@uwaterloo.ca, E-mail: taylor@uwaterloo.ca},
abstractNote = {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 limited mainly to the Local Group. We have searched for faint analogues of Local Group dwarfs around nearby bright galaxies, using a spatial clustering analysis of the photometric catalog of the Sloan Digital Sky Survey (SDSS) Data Release 8. Several other recent searches of SDSS have detected clustered satellite populations down to Δm{sub r} ≡ (m{sub r,} {sub sat} – m{sub r,} {sub main}) ∼ 6-8, using photometric redshifts to reduce background contamination. SDSS photometric redshifts are relatively imprecise, however, for faint and nearby galaxies. Instead, we use angular size to select potential nearby dwarfs and consider only the nearest isolated bright galaxies as primaries. As a result, we are able to detect an excess clustering signal from companions down to Δm{sub r} = 12, 4 mag fainter than most recent studies. We detect an overdensity of objects at separations <400 kpc, corresponding to about 4.6 ± 0.5 satellites per central galaxy, consistent with the satellite abundance expected from the Local Group, given our selection function. Although the sample of satellites detected is incomplete by construction, since it excludes the least and most compact dwarfs, this detection provides a lower bound on the average satellite luminosity function, down to luminosities corresponding to the faintest ''classical'' dwarfs of the Local Group.},
doi = {10.1088/0004-637X/788/2/188},
url = {https://www.osti.gov/biblio/22356544}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 788,
place = {United States},
year = {Fri Jun 20 00:00:00 EDT 2014},
month = {Fri Jun 20 00:00:00 EDT 2014}
}