3 citations · 5 across the 13 of their papers we have counts for
10 papers · 1 filter
A new Chandra look at the globular cluster NGC 6540 and its peculiar X-ray flaring source
A. Sacchi, S. Mereghetti, R. Di Stefano +4
We report the results of a deep ( ks) Chandra exposure of the globular cluster NGC 6540, obtained by combining three observations carried out in 2023-2024 to investigate…
The X-ray-to-UV relation does not evolve in homogeneous quasar samples
G. Risaliti, E. Lusso, E. Nardini +6
We present a new, highly homogeneous quasar sample with X-ray and UV observations optimized to reliably estimate distances via the non-linear X-ray-to-UV relation. Cross-matching t…
A supermassive black hole under the radar: Repeating X-ray variability in a Seyfert galaxy
Matteo Imbrogno, Andrea Sacchi, Giovanni Miniutti +4
In the last few years, a few supermassive black holes (SMBHs) have shown short-term (of the order of hours) X-ray variability. Given the limited size of the sample, every new addit…
Probing the interstellar medium toward GRB 221009A through X-ray dust scattering
B. Vaia, Ž. Bošnjak, A. Bracco +5
The observation of 21 X-ray dust-scattering rings around the extraordinarily bright gamma-ray burst (GRB) 221009A provides a unique opportunity to study the interstellar medium (IS…
Hyperluminous Supersoft X-Ray Sources in the Chandra Catalog
Andrea Sacchi, Kevin Paggeot, Steven Dillmann +2
Hyperluminous supersoft X-ray sources, such as bright extragalactic sources characterized by particularly soft X-ray spectra, offer a unique opportunity to study accretion onto sup…
The restless population of bright X-ray sources of NCG 3621
A. Sacchi, M. Imbrogno, S. E. Motta +9
We report on the multi-year evolution of the population of X-ray sources in the nuclear region of NGC 3621 based on Chandra, XMM-Newton and Swift observations. Among these, two sou…
The X-ray rise and fall of the Recurrent Symbiotic System T CrB
Jesús A. Toalá, Omaira González-Martín, Andrea Sacchi +1
We present the analysis of publicly available NuSTAR, Suzaku and XMM-Newton observations of the symbiotic recurrent nova T CrB covering the 2006.77-2022.66 yr period. The X-ray spe…
Detection of a Highly Ionized Outflow in the Quasi-periodically Erupting Source GSN 069
P. Kosec, E. Kara, L. Brenneman +8
Quasi-periodic eruptions (QPEs) are high-amplitude, soft X-ray bursts recurring every few hours, associated with supermassive black holes. Many interpretations for QPEs were propos…
Front-row seat of the recent R Aqr periastron passage: X-ray multi-epoch spectral and spatial analysis
A. Sacchi, M. Karovska, J. Raymond +7
We report on the X-ray spectral and spatial evolution of the Symbiotic star R Aqr. Through a multi-epoch observational campaign performed with Chandra between 2017 and 2022, we stu…
A soft and transient ultraluminous X-ray source with 6-h modulation in the NGC 300 galaxy
A. Sacchi, P. Esposito, D. de Martino +13
We investigate the nature of CXOU J005440.5-374320 (J0054), a peculiar bright ( erg/s) and soft X-ray transient in the spiral galaxy NGC 300 with a 6-hour per…