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SRGA J181414.6-225604: A New Galactic Symbiotic X-Ray Binary Outburst Triggered by an Intense Mass-loss Episode of a Heavily Obscured Mira Variable.
- Source :
- Astrophysical Journal; 7/26/2022, Vol. 935 Issue 1, p1-24, 24p
- Publication Year :
- 2022
-
Abstract
- We present the discovery and multiwavelength characterization of SRGA J181414.6-225604, a Galactic hard X-ray transient discovered during the ongoing SRG/ART-XC sky survey. Using data from the Palomar Gattini-IR survey, we identify a spatially and temporally coincident variable infrared (IR) source, IRAS 18111-2257, and classify it as a very-late-type (M7â€"M8), long-period (1502 ± 24 days), and luminous (M <subscript> K </subscript> ≠â'9.9 ± 0.2) O-rich Mira donor star located at a distance of â‰14.6<superscript>+2.9</superscript><subscript>â'2.3</subscript> kpc. Combining multicolor photometric data over the last â‰25 yr, we show that the IR counterpart underwent a recent (starting â‰800 days before the X-ray flare) enhanced mass-loss (reaching â‰2.1 Ă— 10<superscript>â'5</superscript> M <subscript>⊙</subscript> yr<superscript>â'1</superscript>) episode, resulting in an expanding dust shell obscuring the underlying star. Multi-epoch follow-up observations from Swift, NICER, and NuSTAR reveal a â‰200 day long X-ray outburst reaching a peak luminosity of L <subscript>X</subscript> ≠2.5 Ă— 10<superscript>36</superscript> erg s<superscript>â'1</superscript>, characterized by a heavily absorbed (N <subscript>H</subscript> ≠6 Ă— 10<superscript>22</superscript> cm<superscript>â'2</superscript>) X-ray spectrum consistent with an optically thick Comptonized plasma. The X-ray spectral and timing behavior suggest the presence of clumpy wind accretion, together with a dense ionized nebula overabundant in silicate material surrounding the compact object. Together, we show that SRGA J181414.6-225604 is a new symbiotic X-ray binary in outburst, triggered by an intense dust-formation episode of a highly evolved donor. Our results offer the first direct confirmation for the speculated connection between enhanced late-stage donor mass loss and the active lifetimes of symbiotic X-ray binaries. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0004637X
- Volume :
- 935
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- 158484604
- Full Text :
- https://doi.org/10.3847/1538-4357/ac7c6e