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Black hole spin estimation of XTE J2012+381 using simultaneous observations of Swift/XRT and NuSTAR
Kumar, Raj
A sufficiently precise measurement of black hole spin is required to carry out quantitative tests of the Kerr metric and to understand several phenomena related to astrophysical black holes. After 24 yr, XTE J2012+381 again underwent an outburst in 2022 December. In this work, we focused on the measurement of the spin and mass of the black hole ca…
LeMMINGs. Multiwavelength constraints on the co-existence of nuclear star clusters and AGN in nucleated galaxies
Argo, M. K.; Gallagher, J. S.; Knapen, J. H. +16 more
The relation between nuclear star clusters (NSCs) and the growth of the central supermassive black holes (SMBHs), as well as their connection to the properties of the host galaxies, is crucial for understanding the evolution of galaxies. Recent observations have revealed that about 10 per cent of nucleated galaxies host hybrid nuclei, consisting o…
NGC 2403 XMM4: evidence for a super-Eddington neutron star with a possible transient pulsation
Roberts, Timothy P.; Luangtip, Wasutep
We present a study of the X-ray source NGC 2403 XMM4 (4XMM J073702.2+653934) based on 20 yr of archival observations with XMM-Newton, Chandra, Swift, and NuSTAR. Although it has previously been classified as an ultraluminous X-ray source (ULX), we show that its luminosity rarely, if ever, passes the $10^{39} \rm \, erg \, s^{-1}$ threshold luminos…
Deuterium fractionation in cold dense cores in the low-mass star-forming region L1688
Caselli, P.; Pineda, J. E.; Sipilä, O. +5 more
In this work, we study deuterium fractionation in four starless cores in the low-mass star-forming region L1688 in the Ophiuchus molecular cloud. We study how the deuterium fraction (RD) changes with environment, compare deuteration of ions and neutrals, core centre and its envelope, and attempt to reproduce the observed results with a …
The nature of very-faint X-ray binaries: near-infrared spectroscopy of 1RXH J173523.7-354013 reveals a giant companion
Maccarone, T. J.; Degenaar, N.; Wijnands, R. +3 more
Very-faint X-ray binaries (VFXBs) are a subclass of black holes and neutron stars in binaries that appear to be accreting at a very low rate. In addition to providing interesting constraints on poorly understood forms of accretion, elucidating the nature of VFXBs is particularly interesting for binary evolution and population modelling. Through ne…
G213.0-0.6, a true supernova remnant or just an H II region?
Han, J. L.; Reich, W.; Gao, X. Y. +2 more
G213.0-0.6 is a faint extended source situated in the anticentre region of the Galactic plane. It has been classified as a shell-type supernova remnant (SNR) based on its shell-like morphology, steep radio continuum spectrum, and high ratio of [S II]/Hα. With new optical emission line data of Hα, [S II], and [N II] recently observed by the Large S…
CO in the Draco nebula: the atomic-molecular transition
Bieging, John H.; Kong, Shuo
This paper presents maps of the J=2-1 transition of CO towards the Draco nebula intermediate-velocity cloud (IVC). The maps cover 8500 square arcmin with a velocity resolution of 0.33 km s$^{-1}$ and angular resolution of 38 ${\rm arcsec}$, or 0.11 pc at the cloud distance of 600 pc. The mapped area includes all the emission detected by the Hersch…
A full reconstruction of two galaxy clusters intra-cluster medium with strong gravitational lensing
Lewis, Geraint F.; Mahler, Guillaume; Hilton, Matt +6 more
Whilst X-rays and Sunyaev-Zel'dovich observations allow to study the properties of the intra-cluster medium (ICM) of galaxy clusters, their gravitational potential may be constrained using strong gravitational lensing. Although being physically related, these two components are often described with different physical models. Here, we present a uni…
Hubble Space Telescope observations of nearby type 1 quasars. I. Characterization of the extended [O III] 5007 Å emission
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +13 more
We use the Hubble Space Telescope to analyse the extended [O III] 5007 Å emission in seven bright radio-quiet type 1 quasars (QSO1s), focusing on the morphology and physical conditions of their extended Narrow-Line Regions (NLRs). We find NLRs extending 3-9 kpc, with four quasars showing roughly symmetrical structures (
ATOMS: ALMA three-millimetre observations of massive star-forming regions-XVII. High-mass star-formation through a large-scale collapse in IRAS 15394-5358
Sanhueza, Patricio; Tej, Anandmayee; Hwang, Jihye +23 more
Hub-filament systems are considered as natural sites for high-mass star formation. Kinematic analysis of the surroundings of hub-filaments is essential to better understand high-mass star formation within such systems. In this work, we present a detailed study of the massive Galactic protocluster IRAS 15394