Search Publications
MaNGA AGN dwarf galaxies (MAD) - I. A new sample of AGNs in dwarf galaxies with spatially-resolved spectroscopy
Domínguez Sánchez, H.; Mezcua, M.
The finding of active galactic nuclei (AGNs) in dwarf galaxies has important implications for galaxy evolution and supermassive black hole formation models. Yet, how AGNs in dwarf galaxies form is still debated, in part due to scant demographics. We use the MaNGA survey, comprising ~10 000 galaxies at z < 0.15, to identify AGN dwarf galaxies us…
Unveiling energy pathways in AGN accretion flows with the warm corona model for the soft excess
Bianchi, S.; Petrucci, P. -O.; De Marco, B. +9 more
The soft excess in active galactic nuclei (AGNs) may arise through a combination of relativistic reflection and the effects of a warm corona at the surface of the accretion disc. Detailed examination of the soft excess can therefore constrain models of the transport and dissipation of accretion energy. Here, we analyse 34 XMM-Newton observations f…
Repeating nuclear transients as candidate electromagnetic counterparts of LISA extreme mass ratio inspirals
Pasham, Dheeraj R.; Zajaček, Michal; Witzany, Vojtěch +2 more
Extreme mass ratio inspirals (EMRIs) are one of the primary targets for the recently adopted millihertz gravitational-wave observatory LISA. Some previous studies have argued that a fraction of all EMRIs form in matter-rich environments, and can potentially explain the dozens of soft X-ray band ($\sim 10^{-1}\,\rm keV$), low-frequency ($\sim 0.1$ …
Narrow-line Seyfert 1 galaxies in Sloan Digital Sky Survey: a new optical spectroscopic catalogue
Stalin, C. S.; Saikia, D. J.; Domínguez, Alberto +1 more
Narrow-line Seyfert 1 (NLSy1) galaxies are an enigmatic class of active galactic nuclei (AGN) that exhibit peculiar multiwavelength properties across the electromagnetic spectrum. For example, these sources have allowed us to explore the innermost regions of the central engine of AGN using X-ray observations and have also provided clues about the …
The detection of polarized X-ray emission from the magnetar 1E 2259+586
Kaaret, Philip; Wu, Kinwah; Enoto, Teruaki +98 more
We report on IXPE, NICER, and XMM-Newton observations of the magnetar 1E 2259+586. We find that the source is significantly polarized at about or above 20 per cent for all phases except for the secondary peak where it is more weakly polarized. The polarization degree is strongest during the primary minimum which is also the phase where an absorpti…
Dark energy survey year 3 results: miscentring calibration and X-ray-richness scaling relations in redMaPPer clusters
Bacon, D.; Smith, M.; Davis, T. M. +77 more
We use Dark Energy Survey Year 3 (DES Y3) clusters with archival XMM-Newton and Chandra X-ray data to assess the centring performance of the redMaPPer cluster finder and to measure key richness observable scaling relations. We find that 10-20 per cent of redMaPPer clusters are miscentred, both when comparing to the X-ray peak position and to the v…
The extreme coronal line emitter AT 2022fpx: varying optical polarization properties and late-time X-ray flare
Reynolds, Thomas M.; Liodakis, Ioannis; Carbajo-Hijarrubia, Juan +8 more
Supermassive black holes disrupt passing stars, producing outbursts called tidal disruption events (TDEs). TDEs have recently gained attention due to their unique dynamics and emission processes, which are still not fully understood. Especially, the so-called optical TDEs are of interest as they often exhibit delayed or obscured X-ray emission fro…
Project Hephaistos - II. Dyson sphere candidates from Gaia DR3, 2MASS, and WISE
Wright, Jason T.; Zackrisson, Erik; Korn, Andreas J. +5 more
The search for extraterrestrial intelligence is currently being pursued using multiple techniques and in different wavelength bands. Dyson spheres, megastructures that could be constructed by advanced civilizations to harness the radiation energy of their host stars, represent a potential technosignature, that in principle may be hiding in public …
Re-energization of AGN head-tail radio galaxies in the galaxy cluster ZwCl 0634.1+47474
Di Gennaro, G.; Brunetti, G.; Shimwell, T. W. +10 more
Low-frequency radio observations show an increasing number of radio galaxies located in galaxy clusters that display peculiar morphologies and spectral profiles. This is the result of the dynamical interaction of the galaxy with the surrounding medium. Studying this phenomenon is key to understanding the evolution of low-energy relativistic partic…
Beyond the Rotational Deathline: Radio Emission from Ultra-long Period Magnetars
Wadiasingh, Z.; Cooper, A. J.
Motivated by the recent detection of ultralong-period radio transients, we investigate new models of coherent radio emission via low-altitude electron-positron pair production in neutron stars (NSs) beyond rotationally powered curvature radiation deathlines. We find that plastic motion (akin to 'continental drift') and qualitatively similar thermo…