J/ApJ/733/87 Star formation efficiency in galaxies (Shi+, 2011)
Extended Schmidt law: role of existing stars in current star formation.
Shi Y., Helou G., Yan L., Armus L., Wu Y., Papovich C., Stierwalt S.
<Astrophys. J., 733, 87 (2011)>
=2011ApJ...733...87S 2011ApJ...733...87S
ADC_Keywords: Galaxies, nearby ; Radio lines
Keywords: galaxies: evolution - galaxies: starburst - ISM: atoms -
ISM: molecules - stars: formation
Abstract:
We propose an "extended Schmidt law" with explicit dependence of the
star formation efficiency (SFE=SFR/Mgas) on the stellar mass surface
density (Σstar). This relation has a power-law index of
0.48±0.04 and a 1σ observed scatter on the SFE of 0.4 dex,
which holds over five orders of magnitude in the stellar density for
individual global galaxies, including various types and especially the
low-surface-brightness (LSB) galaxies that deviate significantly from
the Kennicutt-Schmidt (KS) law. When applying it to regions of a
sample of 12 spiral galaxies at sub-kiloparsec resolution, the
extended Schmidt law not only holds for LSB regions but also shows
significantly smaller scatters both within and across galaxies
compared with the KS law. We argue that this new relation points to
the role of existing stars in regulating the SFE, thus better encoding
the star formation physics. Comparison with physical models of star
formation recipes shows that the extended Schmidt law can be
reproduced by some models including gas free fall in a
stellar-gravitational potential and pressure-supported star formation.
By implementing this new law into the analytic model of gas accretion
in ΛCDM, we show that it can reproduce the observed main
sequence of star-forming galaxies (a relation between the SFR and
stellar mass) from z=0 up to z=2.
Description:
Our whole sample is listed in Table 1 and composed of five sub-samples
including low-redshift late-type galaxies, early-type galaxies, LSB
galaxies, luminous infrared galaxies (LIRGs), and high-z objects. The
CO and HI data are collected from the literature.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 135 143 Samples with CO and HI data
--------------------------------------------------------------------------------
See also:
J/ApJ/708/841 : Star formation in E/S0 galaxies (Wei+, 2010)
J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Name Galaxy name
17- 26 A10 --- Type Galaxy type in this paper (1)
28- 36 F9.6 --- z [-0.0011/3.41] Redshift
38- 45 F8.2 Mpc Dist [0.78/29645] Distance used in this work
47- 73 A27 --- Ap Aperture definition (2)
75- 82 F8.2 kpc2 Area De-projected area used to derive
surface densities
84- 88 F5.2 [Msun/yr/kpc2] logSigSFR Log star formation rate surface density
90- 93 F4.2 [Msun/pc2] logSigG Log of gas surface density
95- 98 A4 --- Ref Reference(s) for SFR and gas
surface density data (3)
100-104 F5.2 [Msun/pc2] logSig* Log of stellar mass surface density
106-132 A27 --- Band Wavelength band used to measure
stellar mass
134-135 A2 --- Ref* [2/18] Reference for stellar mass (3)
--------------------------------------------------------------------------------
Note (1): Type as follows:
LSB = The subsample of low-surface-brightness (LSB) galaxies includes
all the 19 objects from Wyder et al. (2009ApJ...696.1834W 2009ApJ...696.1834W) and
five gas-rich dwarf galaxies from Leroy et al. (2008,
Cat. J/AJ/136/2782).
early-type = We here included nine objects from Wei et al.
(2010ApJ...725L..62W 2010ApJ...725L..62W) and 10 objects from Crocker et al.
(2011MNRAS.410.1197C 2011MNRAS.410.1197C).
high-z-SFG = High-redshift star-forming galaxies (21 optically/near-IR
selected star-forming galaxies (Extended Groth Strip (EGS), BzK,
and BXMD)
high-z-SMG = merging submillimeter galaxies (seven submillimeter objects from
Genzel et al. (2010MNRAS.407.2091G 2010MNRAS.407.2091G))
late-type = This sub-sample includes 61 and 18 objects from Kennicutt
(1998ApJ...498..541K 1998ApJ...498..541K) and Leroy et al. (2008,
Cat. J/AJ/136/2782), respectively.
z=0-LIRGS = Local LIRGs
See section 2.1 for further details.
Note (2): Used to calculate the surface density of SFR, gas and stellar
mass. R25 means the isophotal radius at 25mag/arcsec2 (usually in
B band). Rmax gives the maximum extent of the galaxy at a given
wavelength that is indicated in square brackets. Its value relative
to R25 is listed in parentheses whenever possible. R1/2 is the
half light radius at a given wavelength that is indicated in square
brackets.
Note (3): For those with two RefSg references, the first one is for H2 and
SFR data while the second is for HI data. Reference(s) as follows:
1 = Kennicutt (1998ApJ...498..541K 1998ApJ...498..541K);
2 = Leroy et al. (2008, Cat. J/AJ/136/2782);
3 = Wei et al. (2010ApJ...725L..62W 2010ApJ...725L..62W);
4 = Crocker et al. (2011MNRAS.410.1197C 2011MNRAS.410.1197C);
5 = Wyder et al. (2009ApJ...696.1834W 2009ApJ...696.1834W);
6 = Scoville et al. (1997ApJ...484..702S 1997ApJ...484..702S);
7 = Gracia-Carpio et al. (2007A&A...468L..67G 2007A&A...468L..67G);
8 = Yun & Scoville (1995ApJ...451L..45Y 1995ApJ...451L..45Y);
9 = Bryant & Scoville (1999AJ....117.2632B 1999AJ....117.2632B);
10 = Yun et al. (1994ApJ...430L.109Y 1994ApJ...430L.109Y);
11 = Genzel et al. (2010MNRAS.407.2091G 2010MNRAS.407.2091G);
12 = Oosterloo et al. (2010MNRAS.409..500O 2010MNRAS.409..500O);
13 = Irwin et al. (1987ApJ...313L..91I 1987ApJ...313L..91I);
14 = van Driel & van Woerden (1991A&A...243...71V 1991A&A...243...71V);
15 = Sage & Welch (2006ApJ...644..850S 2006ApJ...644..850S);
16 = Knapp & Raimond (1984A&A...138...77K 1984A&A...138...77K);
17 = Cox et al. (2001AJ....121..692C 2001AJ....121..692C);
18 = this-work.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 09-Nov-2012