J/AJ/143/102 SHELS galaxies with 0.02<z<0.1 (Geller+, 2012)
The faint end of the luminosity function and low surface brightness galaxies.
Geller M.J., Diaferio A., Kurtz M.J., Dell'Antonio I.P., Fabricant D.G.
<Astron. J., 143, 102 (2012)>
=2012AJ....143..102G 2012AJ....143..102G
ADC_Keywords: Galaxy catalogs ; Galaxies, spectra ; Redshifts ;
Photometry, surface
Keywords: galaxies: distances and redshifts - galaxies: fundamental parameters -
galaxies: luminosity function, mass function - galaxies: dwarf
Abstract:
Smithsonian Hectospec Lensing Survey (SHELS) is a dense redshift
survey covering a 4deg2 region to a limiting R=20.6. In the
construction of the galaxy catalog and in the acquisition of
spectroscopic targets, we paid careful attention to the survey
completeness for lower surface brightness dwarf galaxies. Thus,
although the survey covers a small area, it is a robust basis for
computation of the slope of the faint end of the galaxy luminosity
function to a limiting MR=-13.3+5logh. We calculate the faint-end
slope in the R band for the subset of SHELS galaxies with redshifts in
the range 0.02≤z<0.1, SHELS0.1. This sample contains 532 galaxies
with R<20.6 and with a median surface brightness within the half-light
radius of SB50,R=21.82mag/arcsec2. We used this sample to make one
of the few direct measurements of the dependence of the faint end of
the galaxy luminosity function on surface brightness. For the sample
as a whole the faint-end slope, α=-1.31±0.04, is consistent
with both the Blanton et al. analysis of the Sloan Digital Sky Survey
(2005ApJ...631..208B 2005ApJ...631..208B, 2005AJ....129.2562B 2005AJ....129.2562B) and the Liu et al. analysis
of the COSMOS field (2008ApJ...672..198L 2008ApJ...672..198L). This consistency is
impressive given the very different approaches of these three surveys.
A magnitude-limited sample of 135 galaxies with optical spectroscopic
redshifts with mean half-light surface brightness,
SB50,R≥22.5mag/arcsec2 is unique to SHELS0.1. The faint-end
slope is α22.5=-1.52±0.16. SHELS0.1 shows that lower
surface brightness objects dominate the faint-end slope of the
luminosity function in the field, underscoring the importance of
surface brightness limits in evaluating measurements of the faint-end
slope and its evolution.
Description:
The Deep Lens Survey (DLS, Wittman et al., 2006ApJ...643..128W 2006ApJ...643..128W) is an
National Optical Astronomy Observatory (NOAO) key program covering
20deg2 in five separate fields; we use the 4deg2 F2 field at
α=09h19m32.4s and δ=+30°00'00". The DLS photometry
offers the possibility of identifying galaxies with lower surface
brightness. Photometric observations of F2 were made with the MOSAIC I
imager on the KPNO Mayall 4m telescope between 1999 November and 2004
November. We constructed a galaxy catalog from the R-band source list
in F2. We selected galaxy candidates with Kron-Cousins R≤20.6 for
spectroscopic observation.
SHELS (Smithsonian Hectospec Lensing Survey, Geller et al.,
2005ApJ...635L.125G 2005ApJ...635L.125G, 2010ApJ...709..832G 2010ApJ...709..832G) is a redshift survey
covering the DLS survey F2 field. The SHELS spectra cover the
wavelength range 3700-9100Å with a resolution of ∼6Å. SHELS
contains 541 galaxies with R≤20.6 at z≤0.1. We acquired spectra for
the objects with the Hectospec on the MMT from 2004 April 13 to 2007
April 20.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 112 592 SHELS0.1 redshifts
(Smithsonian Hectospec Lensing Survey)
table2.dat 92 86 *Low-redshift candidate list
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Note on table2.dat: list of galaxy candidates below the green line of Fig.7
and without redshifts; the green line is an arbitrary delineation of the
boundary of the SHELS0.1 sample in magnitude-color space
(see section 2.4 for further details).
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See also:
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
J/AJ/139/1857 : Sample of major galaxy pairs at z=0.08-0.38 (Woods+, 2010)
J/AJ/127/704 : Low surface brightness galaxies in SDSS (Kniazev+, 2004)
J/ApJ/591/764 : R magnitudes for 6 nearby galaxy clusters (Christlein+, 2003)
J/ApJS/105/209 : Low surface brightness galaxies. I. The catalog (Impey+ 1996)
http://sdss.physics.nyu.edu/vagc : NYU Value-Added Galaxy Catalog home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- SHELS Smithsonian Hectospec Lensing Survey
(SHELS) identifier (G1)
24- 41 I18 --- objID ? SDSS identifier
43 I1 h RAh [9] Hour of Right Ascension (J2000)
45- 46 I2 min RAm [14/24] Minute of Right Ascension (J2000)
48- 53 F6.3 s RAs Second of Right Ascension (J2000)
54 A1 --- DE- [+] Sign of the Declination
55- 56 I2 deg DEd [28/31] Degree of Declination (J2000)
58- 59 I2 arcmin DEm Arcminute of Declination (J2000)
61- 66 F6.3 arcsec DEs Arcsecond of Declination (J2000)
68- 74 F7.4 mag Rmag [12.5/21] The R band total magnitude (1)
76- 80 A5 --- r_Rmag Source of Rmag (SDSS or DLS) (1)
82- 92 E11.6 --- z Redshift (2)
94- 97 A4 --- r_z Source of z (MMT or SDSS) (3)
99-104 F6.2 km/s e_z [8/150] Redshift uncertainty
106-112 F7.4 mag/arcsec2 muR [18.7/25.6] Observed mean R-band
surface brightness (G2)
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Note (1): The R-band magnitude source is either the DLS (Deep Lens Survey,
2006ApJ...643..128W 2006ApJ...643..128W) or the SDSS (NYU-VAGC catalog); we translate SDSS
r to R using the redshift and the SDSS colors. DLSm or SDSSm indicates
that the magnitudes required a detailed calculation outside the
pipeline for the survey generally as a result of a nearby star and/or
an artifact in the imaging data.
Note (2): The table includes redshifts we obtained for some galaxies
fainter than the survey limit R=20.6 but with redshift z≤0.1.
Note (3): Source as follows:
MMT = redshift from new Hectospec (on the MMT) measurements;
SDSS = redshift from the SDSS (NYU-Value-Added Galaxy Catalog).
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- SHELS Smithsonian Hectospec Lensing Survey
(SHELS) identifier (G1)
24- 41 I18 --- objID SDSS identifier
43 I1 h RAh [9] Hour of Right Ascension (J2000)
45- 46 I2 min RAm [14/24] Minute of Right Ascension (J2000)
48- 53 F6.3 s RAs Second of Right Ascension (J2000)
55- 56 I2 deg DEd [28/31] Degree of Declination (J2000)
58- 59 I2 arcmin DEm Arcminute of Declination (J2000)
61- 66 F6.3 arcsec DEs Arcsecond of Declination (J2000)
68- 74 F7.4 mag Rmag [14.7484/20.5993] The R band magnitude
76- 85 F10.7 mag/arcsec2 muR [18.7406/25.9514] Mean R band surface
brightness (G2)
87- 92 F6.3 mag g-r [-0.08/1.064] (g-r) color index in the
SDSS color
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Global notes:
Note (G1): Objects are in Simbad.
Note (G2): Within the half-light radius µ50,R.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 04-Jun-2013