2021/03/16 by Tanuman Ghosh, Vikram Rana
Physics and Astronomy · #Accretion (finance) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Eddington luminosity #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Luminosity #Physics #RADIUS #Spectral line #Star formation #Stellar mass #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stab774
10 pages, 10 figures; accepted for publication in MNRAS
openalex publication_date 2021/03/16 · arxiv created 2021/03/18 · arxiv updated 2021/03/24 · openalex created_date 2021/03/29 · openalex updated_date 2026/08/05
ABSTRACT We present the results of high-quality XMM-NEWTON observations of a ultraluminous X-ray source (ULX) in the galaxy NGC 4190. The detection of spectral cutoff in NGC 4190 ULX1 spectra rules out the interpretation of the ULX to be in a standard low/hard canonical accretion state. We report that the high quality EPIC spectra can be better described by broad thermal component, such as a slim disc. In addition we found long-term spectral and flux variability in the source using several XMM-NEWTON and Swift data. A clear anticorrelation between flux and power-law photon index is found which further confirms the unusual spectral state evolution of the ULX. Spectral properties of the ULX suggest that the source is in a broadened disc state with luminosities [≈(3 − 10) × 1039 erg s−1] falling in the ultraluminous regime. The positive luminosity–temperature relation further suggests that the multicolour disc model follows the L ∝ T4 relation that is expected for a blackbody disc emission from a constant area and the slim disc model seems to favour L ∝ T2 relation consistent with an advection-dominated disc emission. From the broadened disc-like spectral feature at such luminosity, we estimated the upper limit of the mass of the central compact object from the inner disc radius and found that the ULX hosts a stellar mass black hole.