Search Publications
Circumstellar Medium Constraints on the Environment of Two Nearby Type Ia Supernovae: SN 2017cbv and SN 2020nlb
Swift, Jonathan J.; Galbany, L.; Brown, P. J. +24 more
We present deep Chandra X-ray observations of two nearby Type Ia supernovae, SN 2017cbv and SN 2020nlb, which reveal no X-ray emission down to a luminosity LX ≲ 5.3 × 1037 and ≲ 5.4 × 1037 erg s-1 (0.3-10 keV), respectively, at ~16-18 days after the explosion. With these limits, we constrain the pre-expl…
Sulfuric acid vapor and sulfur dioxide in the atmosphere of Venus as observed by the Venus Express radio science experiment VeRa
Pätzold, M.; Bird, M. K.; Häusler, B. +4 more
The Venus Express radio science experiment VeRa provided more than 900 neutral atmospheric profiles between the years 2006 and 2014. About 800 of these could be used for an analysis of the radio signal absorption at X-Band (wavelength: 3.6 cm), which is mainly caused by sulfuric acid vapor within the Venus atmosphere. The absorptivity profiles wer…
The EXTraS project: Exploring the X-ray transient and variable sky
Salvaterra, R.; Haberl, F.; Greiner, J. +29 more
Temporal variability in flux and spectral shape is ubiquitous in the X-ray sky and carries crucial information about the nature and emission physics of the sources. The EPIC instrument on board the XMM-Newton observatory is the most powerful tool for studying variability even in faint sources. Each day, it collects a large amount of information ab…
The evolution of gas-phase metallicity and resolved abundances in star-forming galaxies at z ≈ 0.6-1.8
Smail, Ian; Bunker, Andrew J.; Swinbank, A. M. +10 more
We present an analysis of the chemical abundance properties of ≈650 star-forming galaxies at $z$ ≈ 0.6-1.8. Using integral-field observations from the K-band multi-object spectrograph (KMOS), we quantify the [N II]/H α emission-line ratio, a proxy for the gas-phase oxygen abundance within the interstellar medium. We define the stellar mass-metalli…
Multicolour photometry and Gaia EDR3 astrometry of two couples of binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324)
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +5 more
This paper presents a comprehensive analysis of two pairs of binary clusters (NGC 5617 and Trumpler 22) and (NGC 3293 and NGC 3324) located in the fourth quadrant of our Galaxy. For this purpose, we use different data taken from VVV survey, WISE, VPHAS, APASS, and GLIMPSE along with Gaia EDR3 astrometric data. We identified 584, 429, 692, and 273 …
Discovery of a Radio Halo (and Relic) in a M500<2×1014 M⊙ Cluster
Di Gennaro, G.; Brunetti, G.; Rossetti, M. +12 more
Radio halos are diffuse synchrotron sources observed in dynamically unrelaxed galaxy clusters. Current observations and models suggest that halos trace turbulent regions in the intracluster medium where mildly relativistic particles are reaccelerated during cluster mergers. Due to the higher luminosities and detection rates with increasing cluster…
Discovery of a recurrent spectral evolutionary cycle in the ultra-luminous X-ray sources Holmberg II X-1 and NGC 5204 X-1
Vasilopoulos, G.; Godet, O.; Webb, N. A. +2 more
Context. Most ultra-luminous X-ray sources (ULXs) are now thought to be powered by stellar-mass compact objects accreting at super-Eddington rates. While the discovery of evolutionary cycles have marked a breakthrough in our understanding of the accretion flow changes in the sub-Eddington regime in Galactic black hole binaries, their evidence in t…
X-ray bounds on cooling, composition, and magnetic field of the Cassiopeia A neutron star and young central compact objects
Ho, Wynn C. G.; Kaplan, D. L.; Heinke, Craig O. +3 more
We present analysis of multiple Chandra and XMM-Newton spectra, separated by 9-19 yr, of four of the youngest central compact objects (CCOs) with ages <2500 yr: CXOU J232327.9+584842 (Cassiopeia A), CXOU J160103.1-513353 (G330.2+1.0), 1WGA J1713.4-3949 (G347.3-0.5), and XMMU J172054.5-372652 (G350.1-0.3). By fitting these spectra with thermal m…
Investigating the Nature of MGRO J1908+06 with Multiwavelength Observations
Torres, Diego F.; Li, Jian; Kerr, Matthew +7 more
The unidentified TeV source MGRO J1908+06, with emission extending from hundreds of GeV to beyond 100 TeV, is one of the most intriguing sources in the Galactic plane. MGRO J1908+06 spatially associates with an IceCube hotspot of neutrino emission. Although the hotspot is not significant yet, this suggests a possible hadronic origin of the observe…
Scalar dark matter candidates revisited
Pradler, Josef; BÅ`hm, Céline; Chu, Xiaoyong +1 more
We revisit the possibility of light-scalar dark matter, in the MeV to GeV mass bracket and coupled to electrons through fermion or vector mediators, in light of significant experimental and observational advances that probe new physics below the GeV scale. We establish new limits from electron colliders and fixed-target beams and derive the streng…