Search Publications
Gravitationally lensed quasars in Gaia - IV. 150 new lenses, quasar pairs, and projected quasars
Treu, T.; Courbin, F.; Anguita, T. +10 more
We report the spectroscopic follow-up of 175 lensed quasar candidates selected using Gaia Data Release 2 observations following Paper III of this series. Systems include 86 confirmed lensed quasars and a further 17 likely lensed quasars based on imaging and/or similar spectra. We also confirm 11 projected quasar pairs and 11 physical quasar pairs,…
Uncovering the geometry of the hot X-ray corona in the Seyfert galaxy NGC 4151 with IXPE
Antonelli, L. A.; Costa, E.; Bianchi, S. +106 more
We present an X-ray spectropolarimetric analysis of the bright Seyfert galaxy NGC 4151. The source has been observed with the Imaging X-ray Polarimetry Explorer (IXPE) for 700 ks, complemented with simultaneous XMM-Newton (50 ks) and NuSTAR (100 ks) pointings. A polarization degree Π = 4.9 ± 1.1 per cent and angle Ψ = 86° ± 7° east of north (68 pe…
Evidence for an abundant old population of Galactic ultra-long period magnetars and implications for fast radio bursts
van der Horst, A. J.; Wadiasingh, Z.; Rajwade, K. M. +3 more
Two recent discoveries, namely PSR J0901-4046 and GLEAM-X J162759.5-523504.3 (hereafter GLEAM-X J1627), have corroborated an extant population of radio-loud periodic sources with long periods (76 and 1091 s, respectively) whose emission can hardly be explained by rotation losses. We argue that GLEAM-X J1627 is a highly magnetized object consistent…
The X-ray polarization of the Seyfert 1 galaxy IC 4329A
Antonelli, L. A.; Costa, E.; Bianchi, S. +105 more
We present an X-ray spectro-polarimetric analysis of the bright Seyfert galaxy IC 4329A. The Imaging X-ray Polarimetry Explorer (IXPE) observed the source for ~500 ks, supported by XMM-Newton (~60 ks) and NuSTAR (~80 ks) exposures. We detect polarization in the 2-8 keV band with 2.97σ confidence. We report a polarization degree of 3.3 ± 1.1 per ce…
The rebrightening of a ROSAT-selected tidal disruption event: repeated weak partial disruption flares from a quiescent galaxy?
Liu, Z.; Buchner, J.; Nandra, K. +11 more
The ROSAT-selected tidal disruption event (TDE) candidate RX J133157.6-324319.7 (J1331) was detected in 1993 as a bright [0.2-2 keV flux of (1.0 ± 0.1) × 10-12 erg s-1 cm-2], ultra-soft (kT = 0.11 ± 0.03 keV) X-ray flare from a quiescent galaxy (z = 0.051 89). During its fifth all-sky survey (eRASS5) in 2022, Spect…
Spectral classification of the 100 pc white dwarf population from Gaia-DR3 and the virtual observatory
Solano, E.; Rebassa-Mansergas, A.; Torres, S. +5 more
The third data release of Gaia has provided low-resolution spectra for ~100 000 white dwarfs (WDs) that, together with the excellent photometry and astrometry, represent an unrivalled benchmark for the study of this population. In this work, we first built a highly complete volume-limited sample consisting in 12 718 WDs within 100 pc from the Sun.…
A real-time transient detector and the living Swift-XRT point source catalogue
Cenko, S. B.; Campana, S.; Kennea, J. A. +5 more
We present the Living Swift-XRT Point Source (LSXPS) catalogue and real-time transient detector. This system allows us for the first time to carry out low-latency searches for new transient X-ray events fainter than those available to the current generation of wide-field imagers, and report their detection in near real time. Previously, such event…
The geometry of the hot corona in MCG-05-23-16 constrained by X-ray polarimetry
Antonelli, L. A.; Costa, E.; Bianchi, S. +105 more
We report on the second observation of the radio-quiet active galactic nucleus MCG-05-23-16 performed with the Imaging X-ray Polarimetry Explorer (IXPE). The observation started on 2022 November 6 for a net observing time of 640 ks, and was partly simultaneous with NuSTAR (86 ks). After combining these data with those obtained in the first IXPE po…
Quasar UV/X-ray relation luminosity distances are shorter than reverberation-measured radius-luminosity relation luminosity distances
Zajaček, Michal; Czerny, Bożena; Khadka, Narayan +5 more
We use measurements of 59/58 quasars (QSOs), over a redshift range 0.0041 ≤ z ≤ 1.686, to do a comparative study of the radius-luminosity (R - L) and X-ray-UV luminosity (LX - LUV) relations and the implication of these relations for cosmological parameter estimation. By simultaneously determining R - L or LX - L
A Gaia view of the optical and X-ray luminosities of compact binary millisecond pulsars
Linares, Manuel; Koljonen, Karri I. I.
In this paper, we study compact binary millisecond pulsars with low- and very low-mass companion stars (spiders) in the Galactic field, using data from the latest Gaia data release (DR3). We infer the parallax distances of the optical counterparts to spiders, which we use to estimate optical and X-ray luminosities. We compare the parallax distance…