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J/AJ/138/1037    Star formation in Centaurus A Group dwarfs       (Cote+ 2009)

Star formation in dwarf galaxies of the nearby Centaurus A Group. Cote S., Draginda A., Skillman E.D., Miller B.W. <Astron. J., 138, 1037-1061 (2009)> =2009AJ....138.1037C
ADC_Keywords: Galaxies, optical ; H II regions ; Photometry, H-alpha Keywords: galaxies: dwarf - galaxies: evolution - galaxies: irregular - H II regions Abstract: We present Hα narrow-band imaging of 17 dwarf irregular (dI) galaxies in the nearby Centaurus A Group. Although all large galaxies of the group are or recently have been through a period of enhanced star formation, the dIs have normal star formation rates (SFRs) and do not contain a larger fraction of dwarf starbursts than other nearby groups such as the Sculptor Group or the Local Group. Most of the galaxies in the group now have fairly accurately known distances, which enables us to obtain relative distances between dIs and larger galaxies of the group. We find four transition dwarfs in the Group, dwarfs that show characteristics of both dE/dSphs and dIs, and which contain cold gas but no current star formation. Description: We observed all of the 19 dwarf irregular (dI) galaxy members of the Centaurus A Group listed in Cote et al. (1997AJ....114.1313C). Of these, 17 were detected and are listed in Table 1. The Hα images, were obtained with the Cerro Tololo Inter-American Observatory (CTIO) 0.9m telescope over 8 nights in 1999 April. The observations usually consisted of 3x1200s through a narrow-band Hα filter centered at 6559Å and with a FWHM of 64Å, followed by a 2x1200s for continuum off-band images through a filter centered at 6115Å and with a FWHM of 140Å. R-band images were also acquired. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 61 17 Centaurus A Group dwarf irregular (dI) galaxies detected in Hα table2.dat 63 22 Star formation properties of Centaurus A Group dI galaxies table3.dat 56 282 HII regions positions and Hα fluxes
See also: J/AJ/133/504 : Galaxies around CenA/M83 galaxy complex (Karachentsev+, 2007) J/MNRAS/346/787 : HIDEEP survey (Minchin+, 2003) J/A+AS/141/469 : First list of the Karachentsev catalog (Huchtmeier+, 2000) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Name Galaxy name 14- 15 I2 h RAh Hour of right ascension (J2000) 17- 18 I2 min RAm Minute of right ascension (J2000) 20- 23 F4.1 s RAs Second of right ascension (J2000) 25 A1 --- DE- Sign of declination (J2000) 26- 27 I2 deg DEd Degree of declination (J2000) 29- 30 I2 arcmin DEm Arcminute of declination (J2000) 32- 33 I2 arcsec DEs Arcsecond of declination (J2000) 35- 37 I3 km/s HV Heliocentric velocity from Cote et al., 1997AJ....114.1313C 39- 42 F4.2 Mpc Dist Distance 44- 47 F4.2 Mpc e_Dist ? Distance uncertainty 49 I1 --- r_Dist [1/2]? Dist reference (1) 51- 56 F6.2 mag BMag Absolute B-band magnitude 58- 61 F4.2 mag e_BMag BMag uncertainty
Note (1): Distances from reference as follows: 1 = Karachentsev et al. (2007, Cat. J/AJ/133/504); 2 = Karachentsev et al. (2002A&A...385...21K)
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Name Galaxy name 13 A1 --- n_Name [cde] Notes (2) 15- 20 E6.2 Msun/yr SFR Total star formation rate (3) 22- 28 E7.2 Msun/yr/Lsun SFR/LB SFR normalized to the galaxy luminosity 30- 35 F6.1 Gyr tForm Estimated star formation timescale 37 A1 --- l_MHI Limit flag on MHI 38- 42 F5.1 10+6Msun MHI Total galaxy HI mass (M(HI)) (4) 44 A1 --- l_MHI/LB Limit flag on MHI/LB 45- 48 F4.2 Msun/Lsun MHI/LB Gas mass normalized to the galaxy luminosity 50 A1 --- l_tGas Limit flag on tGas 51- 56 F6.1 Gyr tGas Gas depletion timescale (5) 58- 63 F6.2 Msun/yr/pc2 SFR/area ? SFR per unit area
Note (2): Flag as follows: c = From Bouchard et al. 2009AJ....137.3038B. d = Hα data from Phillips et al. (1986AJ.....91.1062P), HI mass from Banks et al. (1999ApJ...524..612B), using the nominal distance of 3.8Mpc. e = Hα data from Bouchard et al. (2009AJ....137.3038B), HI mass from Beaulieu et al. (2006AJ....131..325B), using a distance of 4.23Mpc from Jerjen (2000AJ....119..166J). Note (3): The SFRs were calculated using Equation (1) with Hα luminosities obtained by summing all the HII region luminosities listed in Table 3. Equation 1 : SFR(total)=(L(Hα)/(1.26x1041erg/s))M/yr Note (4): Total galaxy HI mass from Cote et al., 1997AJ....114.1313C, adjusted to the distance in Table 1. Note (5): τgas is the gas depletion timescale =(Total Gas Mass)/(SFR), where the total gas mass is 1.32xM(HI) to account for He.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Name Galaxy name 14- 15 I2 --- Num HII region number 17- 18 I2 h RAh Hour of right ascension (J2000) 20- 21 I2 min RAm Minute of right ascension (J2000) 23- 27 F5.2 s RAs Second of right ascension (J2000) 29 A1 --- DE- Sign of declination (J2000) 30- 31 I2 deg DEd Degree of declination (J2000) 33- 34 I2 arcmin DEm Arcminute of declination (J2000) 36- 39 F4.1 arcsec DEs Arcsecond of declination (J2000) 41- 46 F6.1 aW/m2 FHa Hα flux in 10-15erg/cm2/s 48- 51 F4.1 aW/m2 e_FHa FHa uncertainty 53- 56 F4.1 [10-7W] logLHa Log of Hα luminosity in erg/s
Nomenclature Notes: In table 3, HII regions are <[CDS2009] {Name} NN> in Simbad. History: From electronic version of the journal
(End) Emmanuelle Perret [CDS] 20-Jan-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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