J/A+A/567/A68 Gas accretion in nearby spiral galaxies (Di Teodoro+, 2014)
Gas accretion from minor mergers in local spiral galaxies.
Di Teodoro E.M., Fraternali F.
<Astron. Astrophys., 567, A68-68 (2014)>
2014A&A...567A..68D 2014A&A...567A..68D
ADC_Keywords: Galaxies, nearby ; H I data
Keywords: galaxies: interactions - galaxies: evolution -
galaxies: kinematics and dynamics - galaxies: star formation -
galaxies: dwarf
Abstract:
We quantify the gas accretion rate from minor mergers onto
star-forming galaxies in the local Universe using HI observations of
148 nearby spiral galaxies (WHISP sample). We developed a dedicated
code that iteratively analyses HI data-cubes, finds dwarf gas-rich
satellites around larger galaxies, and estimates an upper limit to the
gas accretion rate. We found that 22% of the galaxies have at least
one detected dwarf companion. We made the very stringent assumption
that all satellites are going to merge in the shortest possible time,
transferring all their gas to the main galaxies. This leads to an
estimate of the maximum gas accretion rate of 0.28M☉/yr, about
five times lower than the average star formation rate of the sample.
Given the assumptions, our accretion rate is clearly an overestimate.
Our result strongly suggests that minor mergers do not play a
significant role in the total gas accretion budget in local galaxies.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 73 146 Global properties of the main galaxies selected
from the WHISP sample
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See also:
J/A+A/390/863 : CCD R Photometry of WHISP Dwarf Galaxies (Swaters, 2002)
J/A+A/442/137 : HI observations of WHISP disk galaxies (Noordermeer+, 2005)
J/MNRAS/416/2415 : Morphological parameters of WHISP galaxies (Holwerda+, 2011)
J/MNRAS/416/2437 : Quantified H I morphology of WHISP sample (Holwerda+, 2011)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [UGC]
5- 9 I5 --- UGC UGC galaxy number
11- 18 A8 --- OName Other name of the galaxy
20- 24 F5.1 Mpc Dist Adopted distance (1)
26 I1 --- r_Dist [1/3]? Origin of the distance (2)
28- 31 F4.2 arcmin R25 [0.2/6] Radius R25 (in arcmin) (3)
33- 34 I2 kpc r25 [2/54] Radius R25 (in kpc) (3)
36- 37 I2 deg i [0/90] Inclination angle derived from the axis
ratio in B band as listed in HyperLEDA
39- 43 I5 km/s Vsys Systemic velocity (4)
45- 47 I3 km/s W20 HI-line width at the 20% of the peak flux of
the global HI-line profile (this work)
49- 53 F5.2 GMsun MHI Total HI mass estimated in this work
(in 109M☉)
55- 60 F6.2 GMsun Mb Adopted total baryonic mass (in 109M☉)
62 I1 --- r_Mb [4]? Origin of Mb (2)
64- 67 F4.2 Msun/yr SFR Star formation rate calculated from the 60um
and 100um IRAS fluxes
69 A1 --- l_dMHI/dt Limit flag on dMHI/dt
70- 73 F4.2 Msun/yr dMHI/dt Total gas accretion rate from minor mergers
estimated in this work, including detectable
and "hidden" accretion
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Note (1): We preferably used the EDD catalogue (Tully et al.
2009AJ....138..323T 2009AJ....138..323T, http://edd.ifa.hawaii.edu ), otherwise, we used the
following distance sources, in the given order:
Cosmicflows-2 (Tully et al. 2013AJ....146...86T 2013AJ....146...86T, Cat. J/AJ/146/86);
NED archive; Hubble flow with H0=70km/s/Mpc and systemic velocities
corrected for Virgo-infall taken from the HyperLEDA (Cat. VII/237) catalogue.
Note (2): Notes as follows:
1 = Distance from Cosmicflows-2 catalogue
2 = Distance from NED catalogue
3 = Distance from Hubble flow with Virgo-infall corrected systemic velocity
4 = Baryonic mass from the baryonic Tully-Fisher relation
Note (3): Length of the projected semi-major axis of a galaxy at the isophotal
level 25mag/arcsec2 in the B band. R25 is taken from the HyperLEDA
(Cat. VII/237) catalogue. The radius is converted into kiloparsecs using
the distance in column Dist.
Note (4): systemic velocity measured in this work as the average midpoint
between the velocities at the 20% and 50% of the peak flux of the global
HI-line profile.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 22-Sep-2014