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Simultaneous NICER and NuSTAR observations of the ultraluminous source NGC 4190 ULX-1
Martí, Josep; García, Federico; Fogantini, Federico A. +6 more
Aims: We present an X-ray analysis of three different XMM-Newton observations together with simultaneous NICER and NuSTAR observations of the ultraluminous X-ray source NGC 4190 ULX-1. Our goal is to constrain the structure of the accretion disk and the geometrical properties of the source.
Methods: We performed temporal and spectral ana…
The origin of the soft excess in the luminous quasar HE 1029-1401
Bianchi, S.; Piconcelli, E.; Matt, G. +7 more
The enigmatic and intriguing phenomenon of the "soft excess" observed in the X-ray spectra of luminous quasars continues to be a subject of considerable interest and debate in the field of high-energy astrophysics. This study focuses on the quasar HE 1029-1401 (z = 0.086, log(Lbol/[erg s‑1]) = 46.0 ± 0.2), with a particular e…
Unveiling the origin of the optical and UV emission during the 2017 giant outburst of the Galactic ULX pulsar Swift J0243.6+6124
Mas-Hesse, J. M.; van den Eijnden, J.; Reig, P. +8 more
Context. From late September 2017 to January 2018, the Be X-ray binary (BeXB) Swift J0243.6+6124 underwent a giant outburst that was unprecedently bright. The reported X-ray luminosities were so high that the system was classified as an ultraluminous X-ray source (ULX). It was also the first BeXB pulsar to show radio jet emission. The source was n…
Magnetar as the Central Engine of AT2018cow: Optical, Soft X-Ray, and Hard X-Ray Emission
Dai, Zi-Gao; Li, Long; Zhong, Shu-Qing +3 more
AT2018cow is the most extensively observed and widely studied fast blue optical transient to date; its unique observational properties challenge all existing standard models. In this paper, we model the luminosity evolution of the optical, soft X-ray, and hard X-ray emission, as well as the X-ray spectrum of AT2018cow with a magnetar-centered engi…
The Magnetic Field in the Colliding Filaments G202.3+2.5
Liu, Tie; Liu, Junhao; Lu, Xing +19 more
We observe the magnetic field morphology toward a nearby star-forming filamentary cloud, G202.3+2.5, using James Clerk Maxwell Telescope/POL-2 850 µm thermal dust polarization observations with an angular resolution of 14.″4 (∼0.053 pc). The average magnetic field orientation is found to be perpendicular to the filaments, while showing diffe…
The earliest phases of CNO enrichment in galaxies
Massari, D.; Mucciarelli, A.; Zamorani, G. +3 more
Context. The recent detection of super-solar carbon-to-oxygen and nitrogen-to-oxygen abundance ratios in a group of metal-poor galaxies at high redshift by the James Webb Space Telescope has sparked renewed interest in exploring the chemical evolution of carbon, nitrogen, and oxygen (the CNO elements) at early times and prompted fresh inquiries in…
Unveiling the journey of a highly inclined CME. Insights from the March 13, 2012, event with 110° longitudinal separation
Lario, D.; Jian, L. K.; Temmer, M. +8 more
Context. A fast (∼2000 km s−1) and wide (> 110°) coronal mass ejection (CME) erupted from the Sun on March 13, 2012. Its interplanetary counterpart was detected in situ two days later by STEREO-A and near-Earth spacecraft, such as ACE, Wind, and Cluster. We suggest that at 1 au the CME extended at least 110° in longitude, with Earth …
Constraining the stochastic gravitational wave background using the future lunar seismometers
Zhang, Fan; Chen, Xian; Shao, Lijing +3 more
Motivated by the old idea of using the Moon as a resonant gravitational wave (GW) detector, as well as the recent updates in modeling the lunar response to GWs, we reevaluate the feasibility of using a network of lunar seismometers to constrain the stochastic GW background (SGWB). In particular, using the updated model of the lunar response, we de…
Discovery of a Dusty Yellow Supergiant Progenitor for the Type IIb SN 2017gkk
Niu, Zexi; Sun, Ning-Chen; Liu, Jifeng
Type IIb supernovae are an important subclass of stripped-envelope supernovae (SNe), which show H lines only at early times. Their progenitors are believed to contain a low-mass H envelope before explosion. This work reports the discovery of a progenitor candidate in preexplosion Hubble Space Telescope images for the Type IIb SN 2017gkk. With deta…
Constraining the top-light initial mass function in the extended ultraviolet disk of M 83
Knapen, J. H.; Comerón, S.; Venhola, A. +3 more
Context. The universality or non-universality of the initial mass function (IMF) has significant implications for determining star formation rates and star formation histories from photometric properties of stellar populations.
Aims: We reexamine whether the IMF is deficient in high-mass stars (top-light) in the low-density environment of the…