6 papers
Chandra Rules Out Super-Eddington Accretion Models For Little Red Dots
Andrea Sacchi, Akos Bogdan
One of the most puzzling discoveries by JWST is the population of high-redshift, red, and compact galaxies dubbed little red dots (LRDs). Based on broad-line diagnostics, these gal…
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…
Detection of Anisotropies in the Circumgalactic Medium of Disk Galaxies: Supermassive Black Hole Activity or Star Formation-driven Outflows?
Andrea Sacchi, Akos Bogdan, Nhut Truong
Gamma and X-ray observatories have revealed spectacular structures in the emission of the tenuous hot gas surrounding the Milky Way (MW), known as the Fermi and eROSITA bubbles. Ga…
The impact of periastron passage on the X-ray and optical properties of the Symbiotic System R Aquarii
D. A. Vásquez-Torres, J. A. Toalá, A. Sacchi +4
Multi-epoch Chandra and XMM-Newton observations of the symbiotic system R Aquarii (R Aqr) spanning 22 yr are analysed by means of a reflection model produced by an accretion disc.…
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…