Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

The GALAH survey and symbiotic stars - I. Discovery and follow-up of 33 candidate accreting-only systems

Munari, U. ; Traven, G. LU ; Masetti, N. ; Valisa, P. ; Righetti, G. L. ; Hambsch, F. J. ; Frigo, A. ; Čotar, K. ; De Silva, G. M. and Freeman, K. C. , et al. (2021) In Monthly Notices of the Royal Astronomical Society 505(4). p.6121-6154
Abstract

We have identified a first group of 33 new candidates for symbiotic stars (SySt) of the accreting-only variety among the 600 255 stars so far observed by the GALactic Archaeology with HERMES (GALAH) high-resolution spectroscopic survey of the Southern hemisphere, more than doubling the number of those previously known. GALAH aims to high latitudes and this offers the possibility to sound the Galaxy for new SySt away from the usual plane and bulge hunting regions. In this paper, we focus on SySt of the M spectral type, showing an Hα emission with a peak in excess of 0.5 above the adjacent continuum level, and not affected by coherent radial pulsations. These constraints will be relaxed in future studies. The 33 new candidate SySt were... (More)

We have identified a first group of 33 new candidates for symbiotic stars (SySt) of the accreting-only variety among the 600 255 stars so far observed by the GALactic Archaeology with HERMES (GALAH) high-resolution spectroscopic survey of the Southern hemisphere, more than doubling the number of those previously known. GALAH aims to high latitudes and this offers the possibility to sound the Galaxy for new SySt away from the usual plane and bulge hunting regions. In this paper, we focus on SySt of the M spectral type, showing an Hα emission with a peak in excess of 0.5 above the adjacent continuum level, and not affected by coherent radial pulsations. These constraints will be relaxed in future studies. The 33 new candidate SySt were subjected to an array of follow-up confirmatory observations [X-ray/ultraviolet (UV) observations with the Swift satellite, search for optical flickering, presence of a near-UV upturn in ground-based photometric and spectroscopic data, radial velocity changes suggestive of orbital motion, and variability of the emission-line profiles]. According to Gaia Early Data Release 3 (EDR3) parallaxes, the candidate new SySt are located at the tip of the giant branch, sharing the same distribution in M(Ks) of the well-established SySt. The accretion luminosities of the candidate new SySt are in the range 1-10 L⊙, corresponding to mass accretion rates of 0.1-1 × 10-9 M⊙ yr-1 for white dwarfs of 1 M⊙. The M giant of one of them presents a large lithium overabundance.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; and (Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
accretion, accretion discs, binaries: symbiotic, galaxies: stellar content, methods: data analysis, X-rays: binaries
in
Monthly Notices of the Royal Astronomical Society
volume
505
issue
4
pages
34 pages
publisher
Oxford University Press
external identifiers
  • scopus:85112223818
ISSN
0035-8711
DOI
10.1093/mnras/stab1620
language
English
LU publication?
yes
id
840adf03-d060-4ea8-87cf-dd649dfb6810
date added to LUP
2021-09-23 16:57:47
date last changed
2024-04-20 11:42:04
@article{840adf03-d060-4ea8-87cf-dd649dfb6810,
  abstract     = {{<p>We have identified a first group of 33 new candidates for symbiotic stars (SySt) of the accreting-only variety among the 600 255 stars so far observed by the GALactic Archaeology with HERMES (GALAH) high-resolution spectroscopic survey of the Southern hemisphere, more than doubling the number of those previously known. GALAH aims to high latitudes and this offers the possibility to sound the Galaxy for new SySt away from the usual plane and bulge hunting regions. In this paper, we focus on SySt of the M spectral type, showing an Hα emission with a peak in excess of 0.5 above the adjacent continuum level, and not affected by coherent radial pulsations. These constraints will be relaxed in future studies. The 33 new candidate SySt were subjected to an array of follow-up confirmatory observations [X-ray/ultraviolet (UV) observations with the Swift satellite, search for optical flickering, presence of a near-UV upturn in ground-based photometric and spectroscopic data, radial velocity changes suggestive of orbital motion, and variability of the emission-line profiles]. According to Gaia Early Data Release 3 (EDR3) parallaxes, the candidate new SySt are located at the tip of the giant branch, sharing the same distribution in M(Ks) of the well-established SySt. The accretion luminosities of the candidate new SySt are in the range 1-10 L⊙, corresponding to mass accretion rates of 0.1-1 × 10-9 M⊙ yr-1 for white dwarfs of 1 M⊙. The M giant of one of them presents a large lithium overabundance. </p>}},
  author       = {{Munari, U. and Traven, G. and Masetti, N. and Valisa, P. and Righetti, G. L. and Hambsch, F. J. and Frigo, A. and Čotar, K. and De Silva, G. M. and Freeman, K. C. and Lewis, G. F. and Martell, S. L. and Sharma, S. and Simpson, J. D. and Ting, Y. S. and Wittenmyer, R. A. and Zucker, D. B.}},
  issn         = {{0035-8711}},
  keywords     = {{accretion, accretion discs; binaries: symbiotic; galaxies: stellar content; methods: data analysis; X-rays: binaries}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{4}},
  pages        = {{6121--6154}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{The GALAH survey and symbiotic stars - I. Discovery and follow-up of 33 candidate accreting-only systems}},
  url          = {{http://dx.doi.org/10.1093/mnras/stab1620}},
  doi          = {{10.1093/mnras/stab1620}},
  volume       = {{505}},
  year         = {{2021}},
}