J/MNRAS/454/3664 Abundance gradients in low SB spirals (Bresolin+, 2015)
Abundance gradients in low surface brightness spirals: clues on the origin of
common gradients in galactic discs.
Bresolin F., Kennicutt R.C.
<Mon. Not. R. Astron. Soc., 454, 3664-3673 (2015)>
=2015MNRAS.454.3664B 2015MNRAS.454.3664B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; H II regions ; Abundances
Keywords: H II regions - galaxies: abundances - galaxies: ISM
Abstract:
We acquired spectra of 141 HII regions in 10 late-type low surface
brightness galaxies (LSBGs). The analysis of the chemical abundances
obtained from the nebular emission lines shows that metallicity
gradients are a common feature of LSBGs, contrary to previous claims
concerning the absence of such gradients in this class of galaxies.
The average slope, when expressed in units of the isophotal radius, is
found to be significantly shallower in comparison to galaxies of high
surface brightness. This result can be attributed to the reduced
surface brightness range measured across their discs, when combined
with a universal surface mass density-metallicity relation. With a
similar argument we explain the common abundance gradient observed in
high surface brightness galaxy (HSBG) discs and its approximate
dispersion. This conclusion is reinforced by our result that LSBGs
share the same common abundance gradient with HSBGs, when the slope is
expressed in terms of the exponential disc scalelength.
Description:
We obtained spectra of individual HII regions in the target galaxies
with two different instruments and multislit setups: the Very Large
Telescope equipped with the FOcal Reducer and low dispersion
Spectrograph (FORS) and the Gemini North telescope with the
Multi-Object Spectrograph (GMOS). The FORS data (collected for the
seven ESO galaxies) were obtained with the 300 V grism using
0.9-arcsec slits, while the GMOS data (for the three UGC galaxies)
were obtained with the B600 grating using 1.4-arcsec slits.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 10 Galaxy sample
table3.dat 90 141 Reddening-corrected fluxes
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Gal Galaxy name
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 23 F5.2 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 35 F4.1 arcsec DEs Declination (J2000)
37- 41 A5 --- MType Morphological type
43- 46 F4.1 Mpc Dist Distance
48- 52 F5.1 mag BMAG Absolute B magnitude
54- 56 I3 deg PA Position angle
58- 59 I2 deg i Inclination
61- 62 I2 arcsec r25 Radius of the 25Bmag/arcsec2 isophote
64- 66 F3.1 arcsec e_r25 rms uncertainty on r25
68- 69 I2 kpc rd B-band exponential disc scalelength
71- 73 F3.1 kpc e_rd rms uncertainty on rd
75- 78 F4.1 mag/arcsec+2 SuBrB(0) Dereddened B-band surface brightness
79 A1 --- n_SuBrB(0) [*] Note on SuBrB(0) (1)
81- 87 A7 --- Ref References (2)
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Note (1): * : Not a published value, but derived from the expression
SuBr0(B)=25-r25/rd.
Note (2): References as follows:
1 = PA, i from Auld et al. (2006MNRAS.366.1475A 2006MNRAS.366.1475A)
2 = SuBrB(0) from Beijersbergen et al. (1999A&A...351..903B 1999A&A...351..903B), using SuBrR(0)
and the average SuBrB(0)-SuBrR(0) in their Table 2
3 = PA, i, Type from Matthews & Gallagher (1997AJ....114.1899M 1997AJ....114.1899M)
4 = PA, i from van der Hulst et al. (1993AJ....106..548V 1993AJ....106..548V)
5 = MType from McGaugh et al. (1995AJ....109.2019M 1995AJ....109.2019M)
6 = PA, i from Patterson & Thuan (1996ApJS..107..103P 1996ApJS..107..103P)
7 = rd from McGaugh & Bothun (1994AJ....107..530M 1994AJ....107..530M).
a = B-band exponential disc scalelength rd from Beijersbergen et al.
(1999A&A...351..903B 1999A&A...351..903B, R-band for ESO 440-049)
b = B-band exponential disc scalelength rd from Bell et al.
(2000MNRAS.312..470B 2000MNRAS.312..470B)
c = B-band exponential disc scalelength rd from Lauberts & Valentijn
(1989, Cat. VII/115)
d = B-band exponential disc scalelength rd from McGaugh & Bothun
(1994AJ....107..530M 1994AJ....107..530M)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Gal Galaxy name
13- 14 I2 --- ID HII region sequential number within
the galaxy
16- 17 I2 h RAh Right ascension (J2000)
19- 20 I2 min RAm Right ascension (J2000)
22- 25 F4.1 s RAs Right ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 38 F5.2 arcsec DEs Declination (J2000)
40- 43 F4.2 --- r/r_25 Radius in r25 units
45- 47 I3 --- [OII]3727 ?=- Reddening-corrected flux in [OII]3727
line (on F(Hb)=100 scale)
49- 50 I2 --- e_[OII]3727 ?=- rms uncertainty on [OII]3727
52- 54 F3.1 --- [OIII]4363 ?=- Reddening-corrected flux in [OIII]4363
line (on F(Hb)=100 scale)
56- 58 F3.1 --- e_[OIII]4363 ?=- rms uncertainty on [OIII]4363
60- 62 I3 --- [OIII]5007 Reddening-corrected flux in [OIII]5007
line (on F(Hb)=100 scale)
64- 65 I2 --- e_[OIII]5007 rms uncertainty on [OIII]5007
67- 68 I2 --- [NII]6583 Reddening-corrected flux in [NII]6583
line (on F(Hb)=100 scale)
70 I1 --- e_[NII]6583 rms uncertainty on [NII]6583
72- 74 I3 --- [SII]6731+6717 ?=- Reddening-corrected flux in
[SII]6731+6717 line (on F(Hb)=100 scale)
76- 77 I2 --- e_[SII]6731+6717 ?=- rms uncertainty on [SII]6731+6717
79- 82 F4.2 --- c(Hb) Hβ extinction coefficient
84- 90 E7.3 mW/m2 FHb Measure flux in the Hβ emission line
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Jul-2016