J/MNRAS/406/382 Early-type galaxies in the SDSS Stripe82 (Kaviraj, 2010)
Peculiar early-type galaxies in the Sloan Digital Sky Survey Stripe82.
Kaviraj S.
<Mon. Not. R. Astron. Soc., 406, 382-394 (2010)>
=2010MNRAS.406..382K 2010MNRAS.406..382K
ADC_Keywords: Galaxies, nearby ; Photometry, SDSS ; Redshifts ; Morphology ;
Photometry, ultraviolet
Keywords: galaxies: elliptical and lenticular, cD; galaxies: evolution;
galaxies: formation; galaxies: interactions; galaxies: peculiar
Abstract:
We explore the properties of "peculiar" early-type galaxies (ETGs) in
the local Universe that show (faint) morphological signatures of
recent interactions such as tidal tails, shells and dust lanes.
Standard-depth (∼51s exposure) multicolour galaxy images from the
Sloan Digital Sky Survey (SDSS) are combined with the significantly
(∼2mag) deeper monochromatic images from the public SDSS Stripe82
(-50°<α<59°, -1.25°<δ<1.25°) to extract,
through careful visual inspection, a robust sample of nearby (z<0.05),
luminous (Mr←20.5) ETGs, including a subset of ∼70 peculiar
systems. ∼18% of ETGs exhibit signs of disturbed morphologies (e.g.
shells), while ∼7% show evidence of dust lanes and patches. An
analysis of optical emission-line ratios indicates that the fraction
of peculiar ETGs that are Seyferts or LINERs (19.4%) is twice the
corresponding values in their relaxed counterparts (10.1%). LINER-like
emission is the dominant type of nebular activity in all ETG classes,
plausibly driven by stellar photoionization associated with recent
star formation. An analysis of ultraviolet-optical colours indicates
that, regardless of the luminosity range being considered, the
fraction of peculiar ETGs that have experienced star formation in the
last Gyr is a factor of ∼1.5 higher than that in their relaxed
counterparts. The spectrophotometric results strongly suggest that the
interactions that produce the morphological peculiarities also induce
low-level recent star formation which, based on the recent literature,
are likely to contribute a few per cent of the stellar mass over the
last ∼1Gyr. Peculiar ETGs preferentially inhabit low-density
environments (outskirts of clusters, groups or the field), either due
to high peculiar velocities in clusters making merging unlikely or
because shell systems are disrupted through frequent interactions
within a cluster crossing time.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 191 902 Catalogue of SDSS Stripe82 galaxies sample
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See also:
II/335 : GALEX-GR6/7 data release (Bianchi+ 2014)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/ApJS/210/22 : Herschel Stripe82 survey (HerS) catalog (Viero+, 2014)
J/ApJ/766/109 : Metallicity gradients of elliptical gal. (Kim+, 2013)
J/other/RAA/11.309 : Nearby early-type galaxies in Stripe 82 (Jiang+, 2011)
J/ApJS/186/427 : Detailed morphology of SDSS galaxies (Nair+, 2010)
J/ApJ/697/1369 : GOODS Ks-selected multiwavelength compil. (Bundy+, 2009)
J/MNRAS/388/1537 : Galaxy pairs from SDSS-DR2 (McIntosh+, 2008)
J/AJ/134/579 : SDSS-DR3 morphologically classified galaxies (Fukugita+, 2007)
J/ApJS/162/1 : MUSYC: optical source catalog (Gawiser+, 2006)
J/AJ/130/2647 : Tidal features of 126 nearby red galaxies (van Dokkum+, 2005)
J/AJ/126/1183 : Major galaxy mergers at z≲3 (Conselice+, 2003)
J/AJ/125/1817 : SDSS Early-Type Galaxies Catalog (Bernardi+, 2003)
J/ApJ/565/208 : Galaxy pairs in the CNOC2 Redshift Survey (Patton+, 2002)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: catalog.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [2/3726] Sequence number
6- 23 I18 --- objID SDSS object ID
25- 34 F10.6 deg RAdeg [0.05/359.5] SDSS right ascension (J2000)
36- 44 F9.6 deg DEdeg [-1.25/1.25] SDSS declination (J2000)
46- 53 F8.6 --- z [0.01/0.05] SDSS redshift
55- 63 F9.6 mag umag0 [14.7/19.6] SDSS-DR7 u de-reddened magnitude
65- 73 F9.6 mag gmag0 [12.9/17.1] SDSS-DR7 g de-reddened magnitude
75- 83 F9.6 mag rmag0 [12/16.2] SDSS-DR7 r-band de-reddened magnitude
85- 93 F9.6 mag imag0 [11.6/15.9] SDSS-DR7 i de-reddened magnitude
95-103 F9.6 mag zmag0 [11.3/15.8] SDSS-DR7 z de-reddened magnitude
105-112 F8.6 mag e_umag0 [0.005/0.4] umag0 uncertainty
114-121 F8.6 mag e_gmag0 [0.001/0.01] gmag0 uncertainty
123-130 F8.6 mag e_rmag0 [0.001/0.02] rmag0 uncertainty
132-139 F8.6 mag e_imag0 [0.001/0.02] imag0 uncertainty
141-148 F8.6 mag e_zmag0 [0.001/0.04] zmag0 uncertainty
150-158 F9.6 mag NUV [15/23]?=-1 GALEX NUV dereddened magnitude (DR4)
160-168 F9.6 mag e_NUV [0.002/1]?=-1 NUV uncertainty
170-179 F10.6 mag rMag [-23.2/-20.5] Absolute r-band magnitude M(r)
181-189 F9.6 [Msun] Mhalo [0/14.8]?=-1 Dark matter halo mass from
Yang et al. (2007ApJ...671..153Y 2007ApJ...671..153Y; log scale)
191 I1 --- ETG [1/7] Morphological ETG classification (1)
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Note (1): Each galaxy is morphologically classified by simultaneous
inspection of its multicolour standard-depth image in the SDSS-DR7 and
its deeper monochromatic Stripe82 counterpart. Note that the images
used in this paper are those provided by the public SDSS DR7 release.
The objects are carefully assigned to three main morphological classes
(ETG=early-type galaxies, LTG=late-type galaxies, and "Sa-like"
systems which are bulge-dominated galaxies with faint spiral features
that are visible in the Stripe82 imaging but invisible in the standard
depth images. The ETG population is further subdivided into the
following categories (see section 2 for further explanations):
1 = Relaxed early-type galaxy (ETG)
2 = Peculiar ETG (tidal features)
3 = Peculiar ETG (dust features)
4 = Peculiar ETG (tidal and dust features)
5 = Peculiar ETG (interacting)
6 = Late-type galaxy
7 = Spheroidal galaxy with faint disk features
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Acknowledgement:
Duho Kim <Duho . Kim at asu edu> ; Arizona State University
History:
From catalog sent by Duho Kim downloaded via the adress
http://www.mssl.ucl.ac.uk/~ska/stripe82/skaviraj_stripe82.dat
when it was available.
(End) Emmanuelle Perret [CDS] 16-Dec-2014