J/A+A/574/A126 HeViCS. XVIII. Star-forming dwarf galaxies (Grossi+, 2015) ================================================================================ The Herschel Virgo Cluster Survey. XVIII. Star-forming dwarf galaxies in a cluster environment. Grossi M., Hunt L.K., Madden S.C., Hughes T.M., Auld R., Baes M., Bendo G.J., Bianchi S., Bizzocchi L., Boquien M., Boselli A., Clemens M., Corbelli E., Cortese L., Davies J., De Looze I., di Serego Alighieri S., Fritz J., Pappalardo C., Pierini D., Remy-Ruyer A., Smith M.W.L., Verstappen J., Viaene S., Vlahakis C. =2015A&A...574A.126G ================================================================================ ADC_Keywords: Clusters, galaxy ; Galaxy catalogs ; Photometry, millimetric/submm ; Abundances Keywords: galaxies: dwarf - galaxies: clusters: general - galaxies: ISM - dust, extinction - infrared: ISM Abstract: To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than m_B_=18mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by {beta}=1.5, with a median dust temperature T_d_=22.4K. Assuming {beta}=1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500{mu}m in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of {beta}, while a similarly high fraction (54%) is found if a {beta}-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys, such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and HI fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 10^7^ to 10^11^M_{sun}_) for both dwarfs and spirals. Highly HI-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the large dust-to-gas mass ratios observed in these systems, we find that the fraction of dust removed has to be less than that of the HI component. The cluster environment seems to mostly affect the gas component and star formation activity of the dwarfs. Since the Virgo star-forming dwarfs are likely to be crossing the cluster for the first time, a longer timescale might be necessary to strip the more centrally concentrated dust distribution. Description: Herschel observations were carried out using the SPIRE/PACS parallel scan-map mode with a fast scan speed of 60"/s over two orthogonal crossed-linked scan directions. A total of 8 scans was then obtained for each field, with overlapping regions between the four tiles being covered by 16 scans. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 73 49 Stellar masses, HI and dust masses, SFR, metallicities, HI deficiency and adopted distances of star-forming dwarf galaxies detected by HeViCS tablec1.dat 86 49 Herschel photometry of the sample of Virgo star-forming dwarf galaxies tablec2.dat 80 27 Stellar masses, HI and dust masses, SFR, metallicities, HI deficiency, and distances of the 27 objects selected from the Dwarf Galaxy Survey tablec3.dat 80 12 Stellar masses, HI and dust masses, SFR, metallicities, HI deficiency, and distances of the KINGFISH dwarf galaxy sample tablec4.dat 96 39 Stellar masses, HI and dust masses, SFR, H_2_ masses, HI deficiency and distances of KINGFISH spiral galaxies (from Sa to Sd) tablec5.dat 96 67 Stellar masses, HI and dust masses, SFR, H_2_ masses, HI deficiency, and distances of HeViCS BGC galaxies -------------------------------------------------------------------------------- See also: J/MNRAS/419/3505 : The HeViCS Bright Galaxy Sample (Davies+, 2012) J/MNRAS/428/1880 : Far-IR properties of VCC galaxies (Auld+, 2013) J/A+A/552/A8 : 454 VCC galaxies revised coordinates (di Serego Alighieri+, 2013) J/A+A/562/A106 : Planck submillimetre sources in Virgo Cluster (Baes+, 2014) J/A+A/573/A129 : HeViCS. SPIRE point-source catalogs (Pappalardo+, 2015) Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 A3 --- --- [VCC] 4- 7 I4 --- VCC [1/1791] VCC galaxy number 9- 12 F4.2 [Msun] logM* Stellar mass 14- 17 F4.2 [Msun] e_logM* rms uncertainty on logM* 19 A1 --- l_logMHI Limit flag on logMHI 20- 23 F4.2 [Msun] logMHI HI mass 25- 28 F4.2 [Msun] e_logMHI ? rms uncertainty on logMHI 30- 33 F4.2 [Msun] logMd Dust mass (G1) 34 A1 --- n_logMd [*] Fixed dust temperature (2) 36- 40 F5.2 [Msun/yr] logSFR ?=- Star formation rate 42- 45 F4.2 [Msun/yr] e_logSFR ? rms uncertainty on logSFR 46 A1 --- r_logSFR [abc] Reference for logSFR (3) 48- 51 F4.2 [-] Ab(O)P [8.0/8.9]?=- Abundance 12+log(O/H) from Pilyugin & Thuan (2005ApJ...631..231P) 53- 56 F4.2 [-] e_Ab(O)P ? rms uncertainty on A(O)P 58- 61 F4.2 [-] Ab(O) [7.8/8.5]?=- Abundance 12+log(O/H) 63 A1 --- l_DefHI Limit flag on DefHI 64- 68 F5.2 [-] DefHI [-0.5/1.8] HI deficiency (G2) 70- 73 F4.1 Mpc Dist Adopted distance -------------------------------------------------------------------------------- Note (2): Galaxies noted with (*) correspond to MBB fits with fixed dust temperature, because of the lack of enough data points (see also Table 4). Note (3): References for logSFR as follows: a = SFR calculated from Eq. (4) (Wen et al., 2014MNRAS.438...97W) b = SFR calculated from Eq. (5) (Kennicutt & Evans, 2012ARA&A..50..531K) c = SFR calculated from Eq. (6) (Lee et al., 2009, Cat. J/ApJ/706/599) -------------------------------------------------------------------------------- Byte-by-byte Description of file: tablec1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 A3 --- --- [VCC] 4- 7 I4 --- VCC [1/1791] VCC galaxy number 9 A1 --- l_F100 Limit flag on F100 10- 15 F6.3 Jy F100 Herschel/PACS 100{mu}m flux density 17- 21 F5.3 Jy e_F100 ? rms uncertainty on F100 22 A1 --- n_F100 [+a*] Note on F100 (1) 24 A1 --- l_F160 Limit flag on F160 25- 30 F6.3 Jy F160 Herschel/PACS 160{mu}m flux density 32- 36 F5.3 Jy e_F160 ? rms uncertainty on F160 37 A1 --- n_F160 [a] Note on F160 (1) 39- 43 F5.3 Jy F250 Herschel/SPIRE 250{mu}m flux density 45- 49 F5.3 Jy e_F250 ? rms uncertainty on F250 51 A1 --- l_F350 Limit flag on F350 52- 56 F5.3 Jy F350 Herschel/SPIRE 350{mu}m flux density 58- 62 F5.3 Jy e_F350 ? rms uncertainty on F350 64 A1 --- l_F500 Limit flag on F500 65- 69 F5.3 Jy F500 Herschel/SPIRE 500{mu}m flux density 71- 75 F5.3 Jy e_F500 ? rms uncertainty on F500 76 A1 --- n_F500 [b] Note on F500 (1) 78- 81 F4.1 arcsec a25 Isophotal semi-major axis at B=25mag/arcsec^2^ 83- 86 F4.1 arcsec b25 Isophotal semi-minor axis at B=25mag/arcsec^2^ -------------------------------------------------------------------------------- Note (1): Notes as follows: a = Flux density from Cortese et al. (2014, Cat. J/MNRAS/440/942) b = Time-line photometry from Pappalardo et al. (2015. Cat. J/A+A/573/A129) + = PACS 100um aperture size smaller by a factor ~0.65 compared to other Herschel bands * = PACS 100um aperture size smaller by a factor ~0.50 compared to other Herschel bands -------------------------------------------------------------------------------- Byte-by-byte Description of file: tablec2.dat tablec3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 11 A11 --- Name Galaxy name 13- 17 F5.2 [Msun] logM* ?=- Stellar mass 19- 22 F4.2 [Msun] e_logM* ? rms uncertainty on logM* 24 A1 --- l_logMHI Limit flag on logMHI 25- 29 F5.2 [Msun] logMHI ?=- HI mass 31- 34 F4.2 [Msun] e_logMHI ? rms uncertainty on logMHI 35 A1 --- r_logMHI [a] Reference for logMHI (1) 37- 40 F4.2 [Msun] logMd ?=- Dust mass (G1) 42- 45 F4.2 [Msun] e_logMd ? rms uncertainty on logMd 47- 51 F5.2 [Msun/yr] logSFR ?=- Star formation rate 53- 56 F4.2 [Msun/yr] e_logSFR ? rms uncertainty on logSFR 58- 61 F4.2 [-] Ab(O) [7.5/8.7]?=- Abundance 12+log(O/H) 63- 66 F4.2 [-] e_Ab(O) ? rms uncertainty on 12+log(O/H) 67 A1 --- r_Ab(O) [ac] Reference for 12+log(O/H) (1) 69- 73 F5.2 [-] DefHI ?=- HI deficiency (G2) 75- 79 F5.1 Mpc Dist Distance 80 A1 --- r_Dist [bc] Reference for Dist (1) -------------------------------------------------------------------------------- Note (1): References as follows: a = Remy-Ruyer et al. (2014A&A...563A..31R) b = Madden et al. (2013PASP..125..600M) c = Kennicutt et al. (2011PASP..123.1347K) -------------------------------------------------------------------------------- Byte-by-byte Description of file: tablec4.dat tablec5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 A8 --- Name Galaxy name 10- 14 F5.2 [Msun] logM* ?=- Stellar mass 16- 19 F4.2 [Msun] e_logM* ? rms uncertainty on logM* 21- 25 F5.2 [Msun] logMHI ?=- HI mass 27- 30 F4.2 [Msun] e_logMHI ? rms uncertainty on logMHI 31 A1 --- n_logMHI [ae] Reference for logMHI (1) 33- 36 F4.2 [Msun] logMd Dust mass (G1) 38- 41 F4.2 [Msun] E_logMd rms uncertainty on logMd 43- 46 F4.2 [Msun] e_logMd rms uncertainty on logMd 48- 52 F5.2 [Msun/yr] logSFR ?=- Star formation rate 54- 57 F4.2 [Msun/yr] e_logSFR ? rms uncertainty on logSFR 58 A1 ---- r_logSFR [d] Note on logSFR (1) 59 A1 --- l_logMH2MW Limit flag on logMH2MW 60- 64 F5.2 [Msun] logMH2MW ?=- H_2_ mass from MW conversion factor (2) 65 A1 --- r_logMH2MW [af] Reference for logMH2MW (1) 67 A1 --- l_logMH2Z Limit flag on logMH2MZ 68- 72 F5.2 [Msun] logMH2Z ?=- H_2_ mass from Z conversion factor (2) 73 A1 --- r_logMH2Z [af] Reference for logMH2Z (1) 75- 78 F4.2 [-] Ab(O) [8.1/8.8]?=- Abundance 12+log(O/H) 80- 83 F4.2 [-] e_Ab(O) ? rms uncertainty on 12+log(O/H) 84 A1 --- r_Ab(O) [cg] Reference for 12+log(O/H) (1) 86- 90 F5.2 [-] DefHI HI deficiency (G2) 92- 95 F4.1 Mpc Dist Distance 96 A1 --- r_Dist [ce] Reference for Dist (1) -------------------------------------------------------------------------------- Note (1): References as follows: a = Remy-Ruyer et al. (2014A&A...563A..31R) c = Kennicutt et al. (2011PASP..123.1347K). e = GOLDMine (Gavazzi et al. 2003A&A...400..451G, 2014, arXiv:1401.8123) f = Boselli et al. (2014, Cat. J/A+A/564/A65) g = Hughes et al. (2013, Cat. J/A+A/550/A115) Note (2): H_2_ masses computed with (see Remy-Ruyer et al. 2014A&A...563A..31R) MW = galactic (Milky Way) CO to H_2_ conversion factor Z = CO to H_2_ conversion factor that depends on the metallicity -------------------------------------------------------------------------------- Global notes: Note (G1): Dust masses were determined fitting a single Modified Black Body (MBB: S({nu},T){prop.to}{kappa}_{nu}_.B({nu},T), with the opacity {kappa}_{nu}_{prop.to}({nu}/{nu}_0_)^{beta}^) with a fixed {beta}=1.5 emissivity from 100 to 350{mu}m. Note (G2): the HI deficiency is defined as the logarithmic difference between the HI mass of a reference sample of isolated galaxies for a given morphological type: DefHI=log(M_HI_^ref^/logM_HI_^obs^) -------------------------------------------------------------------------------- History: From electronic version of the journal References: Davies et al., Paper I 2010A&A...518L..48D Cortese et al., Paper II 2010A&A...518L..49C Clemens et al., Paper III 2010A&A...518L..50C Smith et al., Paper IV 2010A&A...518L..51S Grossi et al., Paper V 2010A&A...518L..52G baes et al., Paper VI 2010A&A...518L..53B De Looze et al., Paper VII 2010A&A...518L..54D Davies et al. Paper VIII 2012MNRAS.419.3505D, J/MNRAS/419/3505 Magrini et al., Paper IX 2011A&A...535A..13M Corbelli et al., Paper X 2012A&A...542A..32C Pappalardo et al., Paper XI 2012A&A...545A..75P Auld et al., Paper XII 2013MNRAS.428.1880A, J/MNRAS/428/1880 di Serego Alighieri et al., Paper XIII 2013A&A...552A...8D, J/A+A/552/A8 De Looze et al., Paper XIV 2013MNRAS.436.1057D Baes et al., Paper XV 2014A&A...562A.106B, J/A+A/562/A106 Davies et al. Paper XVI 2014MNRAS.438.1922D Pappalardo et al., Paper XVII 2015A&A...573A.129P, J/A+A/573/A129 ================================================================================ (End) Patricia Vannier [CDS] 09-Mar-2015