2017A&A...606A..77U


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.19CET19:29:09

2017A&A...606A..77U - Astronomy and Astrophysics, volume 606A, 77-77 (2017/10-1)

Star formation in low density HI gas around the elliptical galaxy NGC 2865.

URRUTIA-VISCARRA F., TORRES-FLORES S., MENDES DE OLIVEIRA C., CARRASCO E.R., DE MELLO D. and ARNABOLDI M.

Abstract (from CDS):

Context. Interacting galaxies surrounded by HI tidal debris are ideal sites for the study of young clusters and tidal galaxy formation. The process that triggers star formation in the low-density environments outside galaxies is still an open question. New clusters and galaxies of tidal origin are expected to have high metallicities for their luminosities. Spectroscopy of such objects is, however, at the limit of what can be done with existing 8-10m class telescopes, which has prevented statistical studies of these objects.
Aims. NGC 2865 is a UV-bright merging elliptical galaxy with shells and extended HI tails. In this work we aim to observe regions previously detected using multi-slit imaging spectroscopy.
Methods. We obtained new multi-slit spectroscopy of six young star-forming regions around NGC 2865, to determine their redshifts and metallicities.
Results. The six emission-line regions are located 16-40kpc from NGC 2865 and they have similar redshifts. They have ages of ∼10Myr and an average metallicity of ∼12+log(O/H)∼8.6, suggesting a tidal origin for the regions. We note that they coincide with an extended HI tail, which has projected density of NHI<1019cm–2, and displays a low surface brightness counterpart. These regions may represent the youngest of the three populations of star clusters already identified in NGC 2865.
Conclusions. The high, nearly-solar, oxygen abundances found for the six regions in the vicinity of NGC 2865 suggest that they were formed by pre-enriched material from the parent galaxy, from gas removed during the most recent major merger. Given the mass and the location of the HII regions, we can speculate that these young star-forming regions are potential precursors of globular clusters that will be part of the halo of NGC 2865 in the future. Our result supports the use of the multi-slit imaging spectroscopy as a useful tool for finding nearly-formed stellar systems around galaxies.

Abstract Copyright: © ESO, 2017

Journal keyword(s): ISM: abundances - H II regions - galaxies: dwarf - galaxies: ISM - galaxies: star formation - galaxies: star formation

Simbad objects: 13

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Number of rows : 13

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5441 1
2 NGC 1316 GiP 03 22 41.789 -37 12 29.52 9.81 9.15 8.53 7.66   ~ 1169 1
3 ACO S 373 ClG 03 38 30 -35 27.3           ~ 1499 0
4 RMC 136 Cl* 05 38 42.396 -69 06 03.36   9.63 9.50     ~ 1688 2
5 NGC 2782 Sy2 09 14 05.120 +40 06 49.68 12.29 12.30 11.63     ~ 429 3
6 NGC 2865 GiG 09 23 30.205 -23 09 41.37   12.39 11.43 11.06   ~ 223 0
7 NAME Hydra I Cluster ClG 10 36 36.0 -27 31 04           ~ 765 1
8 NGC 4262 GiG 12 19 30.582 +14 52 39.78 13.00 12.49 11.55     ~ 326 1
9 NGC 4388 Sy2 12 25 46.820 +12 39 43.45 11.91 11.76 11.02     ~ 1164 2
10 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4129 2
11 CD-44 12736 PM* 18 36 25.9487430436 -44 18 36.919462094   10.83 10.22     G0 192 0
12 NGC 7252 IG 22 20 44.7751096408 -24 40 41.905677809 12.26 12.46 12.06 11.57   ~ 659 1
13 NAME Leo Ring HI ~ ~           ~ 41 0

    Equat.    Gal    SGal    Ecl

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2020.01.19-19:29:09

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