2013AJ....146....3S


C.D.S. - SIMBAD4 rel 1.7 - 2021.05.15CEST23:03:43

2013AJ....146....3S - Astron. J., 146, 3 (2013/July-0)

ALFALFA discovery of the nearby gas-rich dwarf galaxy Leo P. III. An extremely metal deficient galaxy.

SKILLMAN E.D., SALZER J.J., BERG D.A., POGGE R.W., HAURBERG N.C., CANNON J.M., AVER E., OLIVE K.A., GIOVANELLI R., HAYNES M.P., ADAMS E.A.K., McQUINN K.B.W. and RHODE K.L.

Abstract (from CDS):

We present KPNO 4 m and LBT/MODS spectroscopic observations of an H II region in the nearby dwarf irregular galaxy Leo P discovered recently in the Arecibo ALFALFA survey. In both observations, we are able to accurately measure the temperature sensitive [O III] λ4363 line and determine a "direct" oxygen abundance of 12 + log(O/H) = 7.17±0.04. Thus, Leo P is an extremely metal deficient (XMD) galaxy, and, indeed, one of the most metal deficient star-forming galaxies ever observed. For its estimated luminosity, Leo P is consistent with the relationship between luminosity and oxygen abundance seen in nearby dwarf galaxies. Leo P shows normal α element abundance ratios (Ne/O, S/O, and Ar/O) when compared to other XMD galaxies, but elevated N/O, consistent with the "delayed release" hypothesis for N/O abundances. We derive a helium mass fraction of 0.2509–0.0123+0.0184, which compares well with the WMAP + BBN prediction of 0.2483±0.0002 for the primordial helium abundance. We suggest that surveys of very low mass galaxies compete well with emission line galaxy surveys for finding XMD galaxies. It is possible that XMD galaxies may be divided into two classes: the relatively rare XMD emission line galaxies which are associated with starbursts triggered by infall of low-metallicity gas and the more common, relatively quiescent XMD galaxies like Leo P, with very low chemical abundances due to their intrinsically small masses.

Abstract Copyright:

Journal keyword(s): galaxies: abundances - galaxies: dwarf - galaxies: evolution

Simbad objects: 14

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Number of rows : 14

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 [PBT2001] SBSG 0335-052 W G 03 37 38.40 -05 02 37.5   19.14     18.85 ~ 99 1
2 SBSG 0335-052 bCG 03 37 44.04 -05 02 38.5     16.65     ~ 440 1
3 SBSG 0335-052B G 03 37 44.04 -05 02 40.2   16.77 16.65   16.79 ~ 155 1
4 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 1021 1
5 UGC 5340 G 09 56 46.047 +28 49 43.77 14.82 14.74 14.59 14.55   ~ 190 1
6 NAME Leo Dwarf Irregular Galaxy G 09 59 26.46 +30 44 47.0 14.08 13.54 13.26 13.33   ~ 559 0
7 NAME Leo P BiC 10 21 45.123 +18 05 16.89           ~ 165 0
8 Feige 34 HS* 10 39 36.7377085527 +43 06 09.209752646 9.613 10.91 11.14 11.319 11.464 sdOp 620 0
9 Mrk 209 bCG 12 26 16.02 +48 29 36.6   15.3       ~ 313 0
10 NAME CVn I dwA GiC 12 38 40.1 +32 45 59 16.91 16.66 16.73 16.62   ~ 204 0
11 UGC 8091 H2G 12 58 40.1930291852 +14 13 00.737117016 15.24 15.16 14.98 14.81   ~ 444 0
12 BD+33 2642 pA* 15 51 59.8857490337 +32 56 54.327647794 9.806 10.61 10.73 10.884 10.961 O7p 388 0
13 NAME Local Void vid 18 38 +18.0           ~ 164 0
14 NAME Sgr dIG G 19 29 59.0 -17 40 41   15.5 13.6     ~ 282 1

    Equat.    Gal    SGal    Ecl

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2021.05.15-23:03:43

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