2009ApJ...696.1834W

Query : 2009ApJ...696.1834W

2009ApJ...696.1834W - Astrophys. J., 696, 1834-1853 (2009/May-2)

The star formation law at low surface density.

WYDER T.K., MARTIN D.C., BARLOW T.A., FOSTER K., FRIEDMAN P.G., MORRISSEY P., NEFF S.G., NEILL J.D., SCHIMINOVICH D., SEIBERT M., BIANCHI L., DONAS J., HECKMAN T.M., LEE Y.-W., MADORE B.F., MILLIARD B., RICH R.M., SZALAY A.S. and YI S.K.

Abstract (from CDS):

We investigate the nature of the star formation law at low gas surface densities using a sample of 19 low surface brightness (LSB) galaxies with existing H I maps in the literature, UV imaging from the Galaxy Evolution Explorer satellite, and optical images from the Sloan Digital Sky Survey. All of the LSB galaxies have (NUV - r) colors similar to those for higher surface brightness star-forming galaxies of similar luminosity indicating that their average star formation histories are not very different. Based upon four LSB galaxies with both UV and far-infrared (FIR) data, we find FIR/UV ratios significantly less than 1, implying low amounts of internal UV extinction in LSB galaxies. We use the UV images and H I maps to measure the star formation rate (SFR) and hydrogen gas surface density within the same region for all the galaxies. The LSB galaxy star formation rate surface densities lie below the extrapolation of the power law fit to the SFR surface density as a function of the total gas density for higher surface brightness galaxies. Although there is more scatter, the LSB galaxies also lie below a second version of the star formation law in which the SFR surface density is correlated with the gas density divided by the orbital time in the disk. The downturn seen in both star formation laws is consistent with theoretical models that predict lower star formation efficiencies in LSB galaxies due to the declining molecular fraction with decreasing density.

Abstract Copyright: ∼

Journal keyword(s): galaxies: evolution - galaxies: irregular - galaxies: ISM - galaxies: spiral - ultraviolet: galaxies

Simbad objects: 26

Full paper

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Number of rows : 26

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Mag R	Sp type	#ref 1850 - 2024	#notes
1	M 33	GiG	01 33 50.8965749232	+30 39 36.630403128	6.17	6.27	5.72		~	5847	1
2	M 74	G	01 36 41.7451236624	+15 47 01.107512304	10.52	10.00	9.46	9.16	~	1741	1
3	AGC 180072	LSB	08 09 32.6	+22 33 34					~	49	0
4	LEDA 86665	LSB	08 46 37.90	+18 53 23.7		17.21			~	49	0
5	LSB F563-1	LSB	08 55 01.4	+19 45 06					~	68	0
6	LEDA 86668	LSB	09 02 53.357	+20 04 32.21		16.9			~	100	0
7	LEDA 86670	LSB	09 37 36.6	+21 46 15					~	51	0
8	LSB F568-1	LSB	10 25 42.1	+22 25 28					~	63	0
9	LSB F568-3	LSB	10 26 59	+22 13.6					~	79	0
10	UGC 5750	AG?	10 35 45.12	+20 59 24.9		17			~	76	0
11	2MASS J10395248+2050493	LIN	10 39 52.4820927048	+20 50 49.375560660		14.20			~	96	0
12	LEDA 86672	LSB	10 45 02.064	+22 03 15.54					~	83	0
13	UGC 5999	LSB	10 52 58.652	+07 37 11.27		18			~	54	0
14	UGC 6151	GiC	11 05 56.2923063720	+19 49 34.555257336	14.52	14.80	14.39		~	60	1
15	CAIRNS J113731.30+183536.3	LSB	11 37 31.30	+18 35 36.3					~	9	0
16	UGC 6614	LIN	11 39 14.8736598984	+17 08 37.200948684		14.8			~	149	0
17	UGC 7321	EmG	12 17 34.021	+22 32 23.35		14.07		13.21	~	264	0
18	2MASX J12365934+1419494	LSB	12 36 59.3463193464	+14 19 49.164305988		17.80			~	202	0
19	LSB F574-1	LSB	12 38 13.3	+22 17 59					~	60	0
20	LSB F574-2	LSB	12 46 47.3	+21 48 12					~	26	0
21	M 51	Sy2	13 29 52.698	+47 11 42.93		9.26	8.36	8.40	~	4333	4
22	LEDA 86676	LSB	13 50 10.3	+18 16 06					~	25	0
23	UGC 9024	LSB	14 06 40.543	+22 04 12.18		16.0			~	54	0
24	VLSB F579-V01	LSB	14 32 48.1	+22 45 58					~	38	0
25	LEDA 86657	LSB	15 57 27.483	+20 39 59.12					~	99	0
26	NGC 7331	LIN	22 37 04.0506038088	+34 24 56.800076508	10.65	10.35	9.48		~	1228	2

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