Multiwavelength Properties of the SDSS Galaxies in Various Classes Feb 19, 2008 Joon Hyeop Lee 1, Myung Gyoon Lee 1, Changbom Park 2, Yun-Young Choi 2 1 Seoul National University 2 Korea Institute for Advanced Study SDSS-KSG Workshop

Introduction 1. Why “Galaxies in Various Classes”? It is important to understand the relationships between galaxies with different features. Why are you different from me? … Why galaxies are so diverse? How galaxies form and evolve? How different are the diverse galaxies?

Introduction 1. Why “Galaxies in Various Classes”? In many previous studies, galaxies have been investigated, using various classification: morphology, color, spectral features, and so on. - Morphology (early-type vs. late-type): Choi et al. (2007),... - Color (red vs. blue): Martin et al. (2007),... - Spectral features (passive vs. star-forming vs. Seyfert vs. LINER): Mateus et al. (2006)... ? early-type = red = passive ? ? late-type = blue = star-forming ? NOT ALWAYS ! Blue early-type galaxies: elliptical morphology, but blue color. (Abraham et al. 1999; Ferreras et al. 2005; Lee et al. 2006) Passive spiral galaxies: spiral morphology, but no signal of current SF. (Couch et al. 1998; Goto 2003; Yamauchi & Goto 2004) A systematic study based on a fine classification is necessary.

2. Why “Multiwavelength”? Multi-wavelength data provide diverse information about galaxy evolution, such as dust contents, recent star formation history, and optically-obscured AGNs. - Chang et al. (2006): elliptical galaxies in the optical and NIR bands - Goto (2005): IR galaxies in the optical and IR bands - Ivezic (2002): radio galaxies in the optical and radio bands - Yi et al. (2005): early-type galaxies in the optical and UV bands - Anderson (2007): X-ray AGNs in the optical and X-ray bands However, systematic studies using all wavelength data are not sufficient, yet. - Obric et al. (2006): a panchromatic study based on the SDSS DR1, using SDSS, ROSAT, GALEX, 2MASS, IRAS, GB6, FIRST, NVSS and WENSS data.

3. Purpose Understand the properties of galaxies in various fine classes based on their morphology, color and spectral features, using multi-wavelength data. Constraints on the large picture of galaxy evolution

Data Sloan Digital Sky Survey (SDSS) - ugriz bands - 1.4” FWHM – 9200 Å spectroscopy sq.degree (+ DR4plus, MPA catalog) optical Two Micron All Sky Survey (2MASS) - JHKs bands - 3” FWHM % of all sky near-infrared Infrared Astronomical Satellite (IRAS) Survey - 98% of all sky - 12, 25, 60 and 100 μm mid- & far-infrared Faint Images of the Radio Sky at Twenty-centimeters (FIRST) Survey GHz (20cm) - 5” resolution - over sq.degree radio

Galaxy Evolution Explorer (GALEX) Survey - FUV(1528 Å ) - NUV(2271 Å ) - 4.5–6.5” resolution ultraviolet Roentgen Satellite (ROSAT) Survey keV - all sky - 22” resolution X-ray

Analysis 1.Galaxy Classification (1) Morphology (2) Color (3) Spectral Features Park & Choi (2005) Early-type Late-type Lee et al. (2006) Red Blue Kauffmann et al. (2003) Kewley et al. (2006) AGN H II LINER Seyfert →Early-type galaxies Late-type galaxies →Red galaxies Blue galaxies →Passive,H II, Seyfert, LINER

morphology color spectral features blue red early-type late-type passive H II Seyfert LINER

2.Sample Selection K-correction: Blanton et al. (2003) Evolutionary correction: Tegmark et al. (2004) Completeness limit: 14.5<r pet <17.77

(1)REGs have consistent colors with the 6-8 Gyr SSP. (2)The pRLGs have consistent colors with REGs, and RLGs are located on a sequence from REG colors to decreasing (u-r) and increasing (r-Ks). (3)The pBEGs, lBEGs are consistent with young SSP, but hBEGs, sBEGs have bluer (u-r) and redder (r-Ks). (4)BLGs have younger mean stellar age than any other morphology-color class. Results 1.Near-Infrared (2MASS)

(1)REGs have consistent colors with the 6-8 Gyr SSP. (2)The pRLGs have consistent colors with REGs, and RLGs are located on a sequence from REG colors to decreasing (u-r) and increasing (r-Ks). (3)The pBEGs, lBEGs are consistent with young SSP, but hBEGs, sBEGs have bluer (u-r) and redder (r-Ks). (4)BLGs have younger mean stellar age than any other morphology-color class. Results 1.Near-Infrared (2MASS)

Galactic Downsizing (Cowie et al. 1996) (1)REGs have consistent colors with the 6-8 Gyr SSP. (2)The pRLGs have consistent colors with REGs, and RLGs are located on a sequence from REG colors to decreasing (u-r) and increasing (r-Ks). (3)The pBEGs, lBEGs are consistent with young SSP, but hBEGs, sBEGs have bluer (u-r) and redder (r-Ks). (4)BLGs have younger mean stellar age than any other morphology-color class. Results 1.Near-Infrared (2MASS)

2.Mid- and Far-Infrared (IRAS) (1)Blue galaxies are better detected than red galaxies (Obric et al. 2006), and late-type galaxies are better detected than early-type galaxies. (2)99% of the IRAS-detected objects are non-passive. (3)BLGs are better detected than RLGs, which shows that the dominant factor to make RLGs red may be the bulge-to-disk ratio rather than dust contents.

3.Radio (FIRST) Best et al. (2005) and Croft et al. (2007) showed that the fraction of radio-loud AGN host galaxies is a strong function of stellar mass. Early-type radio source: radio-loud AGNs. Late-type radio source: star formation regions.

4.Ultraviolet (GALEX) The pRLGs have consistent UV colors with non-passive REGs. The non-passive RLGs have consistent (NUV-r) colors with BEGs. The pBLGs have very blue UV colors.

4.Ultraviolet (GALEX) The pRLGs have consistent UV colors with non-passive REGs. The non-passive RLGs have consistent (NUV-r) colors with BEGs. The pBLGs have very blue UV colors. UV colors are very sensitive to recent star formation history. The pBEGs are not well explained by the SSP model.

4.Ultraviolet (GALEX) The pRLGs have consistent UV colors with non-passive REGs. The non-passive RLGs have consistent (NUV-r) colors with BEGs. The pBLGs have very blue UV colors. UV colors are very sensitive to recent star formation history. The pBEGs are not well explained by the SSP model.

5.X-ray (ROSAT) Red galaxies are better detected than blue galaxies in the X-ray (73% of x-ray sources are red galaxies), which is consistent with Obric et al. (2006). The sample sizes are too small to compare the X- ray properties between fine classes.

 The NIR colors show that REGs are well explained by SSP models, and that RLGs may have both old and young populations. BEGs seem much younger than REGs, and BLGs have the youngest age.  Dust extinction may not be the dominant factor to make RLGs look red, because they are less detected in the MIR and FIR bands, than BLGs.  The bright REGs are obviously better detected in the radio band, using the FIRST data, than faint REGs, whereas the radio detection rate of late-type galaxies is not very dependent on their absolute magnitude, except for pRLGs.  The UV colors of BEGs are explained by old SSP galaxies with additional young stellar populations. The pRLGs have very consistent UV colors with non-passive REGs.  Since the X-ray detection rate in each class, using the ROSAT data, is too small, meaningful discussions for individual classes are very difficult in the X-ray bands. Summary

Distance to the n th -nearest neighbor - Cooper et al. (2005) showed that the projected n-th nearest neighbor distance measure (Dressler 1980) provides more accurate estimate of local density over a continuous and broad range of scales, than the aperture count (Hogg et al. 2003) or the Voronoi volume (Ramella et al. 2001). In this study, the projected distance to the 5 th -nearest neighbor is defined as: The projected comoving distances to 5 th -nearest neighbors from a target objects, within a redshift slice limited as ±1000 km/s with respect to the recession velocity of the target object, in the given volume. 6.Environmental Effects

NIRMIR+FIR radio UV X-ray ?

morphology color spectral features blue red early-type late-type passive H II Seyfert LINER