J/ApJ/708/841 Star formation in E/S0 galaxies (Wei+, 2010)
Gas mass fractions and star formation in blue-sequence E/S0 galaxies.
Wei L.H., Kannappan S.J., Vogel S.N., Baker A.J.
<Astrophys. J., 708, 841-861 (2010)>
=2010ApJ...708..841W 2010ApJ...708..841W
ADC_Keywords: Galaxies, nearby ; H I data ; Spectroscopy ; Surveys
Keywords: galaxies: elliptical and lenticular, cD - galaxies: evolution
Abstract:
Recent work has identified a population of low-redshift E/S0 galaxies
that lie on the blue sequence in color versus stellar mass parameter
space, where spiral galaxies typically reside. While high-mass
blue-sequence E/S0s often resemble young merger or interaction
remnants likely to fade to the red sequence, we focus on blue-sequence
E/S0s with lower stellar masses (M*<a fewx1010M☉), which are
characterized by fairly regular morphologies and low-density field
environments where fresh gas infall is possible. This population may
provide an evolutionary link between early-type galaxies and spirals
through disk regrowth. Focusing on atomic gas reservoirs, we present
new GBT HI data for 27 E/S0s on both sequences as well as a complete
tabulation of archival HI data for other galaxies in the Nearby Field
Galaxy Survey. Normalized to stellar mass, the atomic gas masses for
12 of the 14 blue-sequence E/S0s range from 0.1 to >1.0, demonstrating
that morphological transformation is possible if the detected gas can
be converted into stars. These gas-to-stellar mass ratios are
comparable to those of spiral and irregular galaxies and have a
similar dependence on stellar mass.
Description:
We consider a subsample of the Nearby Field Galaxy Survey (NFGS) E/S0
galaxies (Jansen et al. (2000, Cat. J/ApJS/126/331 and Cat.
J/ApJS/126/271)) for detailed study of the M* regime where Kannappan
et al., 2009AJ....138..579K 2009AJ....138..579K, report abundant blue-sequence E/S0s.
The new HI observations were obtained with the GBT Spectrometer in the
L band, with 50MHz bandwidth, one spectral window, and nine sampling
levels, in 10 minute on-off source pairs (5 minutes per position)
during 2007 March and October.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 200 H I data for the NFGS
table2.dat 89 35 New H I data for the 27 sources subsample
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See also:
VIII/77 : HI spectral properties of galaxies (Springob+, 2005)
VIII/73 : HI Parkes All Sky Survey Catalogue (HIPASS) (Meyer+, 2004)
VII/238 : HYPERLEDA. II. Homogenized HI data (Paturel+, 2003)
VII/237 : HYPERLEDA. I. Catalog of galaxies (Paturel+, 2003)
VIII/68 : Huchtmeier-Richter HI catalog (Huchtmeier+ 1989)
J/PASP/117/227 : Properties of 101 galaxies from the NFGS (Kewley+, 2005)
J/AJ/127/2002 : Star Formation Rate of NFGS galaxies (Kewley+, 2004)
J/ApJS/126/331 : Spectrophotometry of nearby field galaxies (Jansen+ 2000)
J/ApJS/126/271 : Surface photometry of nearby field galaxies (Jansen+ 2000)
J/AJ/116/2738 : Spectroscopy of early-type galaxies (Scodeggio+ 1998)
http://www.public.asu.edu/~rjansen/nfgs/ : NFGS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- NFGS NFGS identification number
5- 16 A12 --- Name Galaxy name (G1)
18- 23 A6 --- UGC The UGC number
25- 28 A4 --- MType Morphology in NFGS database
30- 32 A3 --- Seq Sequence association (B, Mid or R) (1)
34- 38 I5 km/s HVel ? Heliocentric optical velocity from HI
40- 41 I2 km/s e_HVel ? Uncertainty in HVel
43- 45 I3 km/s Vmax ? Observed maximum rotation speed
47- 50 F4.1 km/s e_Vmax ? Uncertainty in Vmax
52 A1 --- l_fHI Limit flag on fHI
53- 57 F5.2 Jy.km/s fHI ? Velocity-integrated HI flux
59- 62 F4.2 Jy.km/s e_fHI ? Uncertainty in fHI
64 A1 --- l_MHI Limit flag on MHI
65- 71 E7.2 Msun MHI ? HI gas mass (2)
73- 79 E7.2 Msun e_MHI ? Uncertainty in MHI
81 A1 --- Sample? [X] In the sub-Mb E/SO sample? (27 sources)
83- 86 A4 --- Ref Reference for HI data (3)
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Note (1): (red, blue, or mid) if M* and U-R color are available, see Figure 1.
Note (2): Calculated from fHI following Haynes & Giovanelli
(1984AJ.....89..758H 1984AJ.....89..758H).
Note (3): Reference as follows:
GBT = new GBT observations presented in this paper;
LE = HyperLeda (Paturel et al. 2003, Cat. VII/237 and VII/238);
HR = A General Catalog of HI Observations of Galaxies (Huchtmeier &
Richter 1989, Cat. VIII/68);
CEGG = Cornell EGG HI Digital Archive (Springob et al. 2005, Cat. VIII/77);
HI = HIPASS (Barnes et al. 2001MNRAS.322..486B 2001MNRAS.322..486B; Cat. VIII/73).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- NFGS [1/197] NFGS identification number
5- 16 A12 --- Name Galaxy name (G1)
17 A1 --- f_Name [a-c] Flag on Name (1)
19- 24 A6 --- UGC UGC designation
26- 27 I2 h RAh Hour of right ascension of GBT pointing center
(J2000)
29- 30 I2 min RAm Minute of right ascension (J2000)
32- 35 F4.1 s RAs Second of right ascension (J2000)
37 A1 --- DE- Sign of declination of GBT pointing center
(J2000)
38- 39 I2 deg DEd Degree of declination (J2000)
41- 42 I2 arcmin DEm Arcminute of declination (J2000)
44- 45 I2 arcsec DEs Arcsecond of declination (J2000)
47- 50 I4 s Tint Time on-source
52- 56 I5 km/s HVel ? Heliocentric optical velocity from HI
58- 59 I2 km/s e_HVel ? HVel uncertainty
61- 63 I3 km/s W20 ? Velocity width measured at the 20% level
65- 66 I2 km/s e_W20 ? W20 uncertainty
68- 70 I3 km/s W50 ? Velocity width measured at the 50% level
72- 73 I2 km/s e_W50 ? W50 uncertainty
75 A1 --- l_fHI Limit flag on fHI
76- 79 F4.2 Jy.km/s fHI Velocity-integrated HI flux (2)
81- 84 F4.2 Jy.km/s e_fHI ? fHI uncertainty
86- 89 F4.2 mJy Sig Channel-to-channel rms of the HI spectrum
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Note (1): Flag as follows:
a = The companion flux noted for this galaxy may in fact belong to NGC 4308,
although the offset between the optical and measured HI velocity suggests
that the flux belongs to a nearby companion.
b = The measured HI velocity suggests that the flux belongs to a nearby
companion.
c = Preliminary VLA HI data (L. H. Wei et al. 2010ApJ...725L..62W 2010ApJ...725L..62W) suggest
that UGC 12265N contains about 1/4 of total HI within the GBT beam, so
we use this fraction of the total HI flux for our analysis.
Note (2): For galaxies with large companions in the GBT beam, we measure
the HI flux twice. The first row contains values measured in the
ionized-gas/stellar velocity range, or upper limits if the galaxy is
undetected. The second row includes companion flux (if any) within
±300km/s of the target galaxy. Please see Section 2.2.3 for more details.
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Global notes:
Note (G1): NGC number, IC number, or IAU anonymous notation.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 13-Feb-2012