Astronomers from Taiwan have carried out X-ray observations of the galaxy NGC 1559 utilizing NASA’s Chandra spacecraft. They detected eight new ultraluminous X-ray sources on this galaxy. The discovering is reported in a paper revealed August 10 on the pre-print server arXiv.
Ultraluminous X-ray sources (ULXs) are level sources within the sky which might be so vibrant in X-rays that every emits extra radiation than 1 million suns emit in any respect wavelengths. They’re much less luminous than active galactic nuclei (AGN), however extra constantly luminous than any recognized stellar course of. Though quite a few research of ULXs have been carried out, the essential nature of those sources nonetheless stays unsolved.
At a distance of some 41 million light years, NGC 1559 is a barred spiral galaxy within the constellation Reticulum. Regardless of its fragmented morphology, the spiral arms of NGC 1559 are comparatively large with a excessive star-formation fee. The galaxy can also be recognized for internet hosting a minimum of 4 supernovae within the final 40 years.
A crew of astronomers led by Chen-Hsun Ma of the Nationwide Cheng Kung College in Taiwan, has investigated NGC 1559 with Chandra’s Superior CCD Imaging Spectrometer (ACIS), specializing in vibrant X-ray level sources. The observations resulted within the identification of 33 X-ray level sources, out of which eight turned out to be new ULXs.
“We report a research of the X-ray inhabitants in NGC 1559 utilizing the Chandra/ACIS remark taken in 2016. 33 X-ray level sources had been detected. Amongst these, there are eight ULXs with X-ray luminosities increased than 1039 erg/s,” the researchers wrote within the paper.
Probably the most luminous ULX out of the eight reported within the research is the one designated X-17. It has an X-ray luminosity of about 7.98 duodecillion erg/s in 0.3–7 keV. The astronomers famous that the X-ray luminosity of X-17 even exceeds 10 duodecillion erg/s when contemplating the higher certain of the error.
One other new ULX value noticing is the supply designated X-6. It’s the weakest ULX in NGC 1559, with an X-ray luminosity at a degree of 1.06 duodecillion erg/s. Subsequently, it might fall into the non-ULX regime. Furthermore, X-6 has a photon index bigger than 2.5, what signifies a doable thermal origin of the emission—opposite to the opposite seven ULX which might be non-thermal methods.
The authors of the paper underlined that NGC 1559 hosts an unexpectedly giant variety of ULXs. They provide few hypotheses that might clarify this overabundance of those sources within the investigated galaxy.
“We now have tried to elucidate the surplus of ULXs utilizing the arguments of low-metallicity or starburst and in contrast with related circumstances of different close by galaxies. Sadly, there’s nonetheless no passable clarification,” the researchers concluded.
Extra data:
Chen-Hsun Ma et al, Chandra Commentary of NGC 1559: Eight Ultraluminous X-ray Sources Together with a Compact Binary Candidate, arXiv (2023). DOI: 10.48550/arxiv.2308.06287
Journal data:
arXiv
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Astronomers uncover eight ultraluminous X-ray sources in NGC 1559 (2023, August 22)
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