Related papers: On the Nova Rate in M87
We present the first JWST+NIRCam images of the giant elliptical active galaxy M87 and its jet at 0.90, 1.50, 2.77 and 3.56 $\mu$m. We analysed the large-scale jet structure, identifying prominent components, and determined the near-infrared…
[Abridged] Classical novae (CNe) represent the major class of supersoft X-ray sources (SSSs) in the central region of our neighbouring galaxy M 31. We performed a dedicated monitoring of the M 31 central region with XMM-Newton and Chandra…
This is the first paper of a series in which we present new measurements of the observed rates of supernovae (SNe) in the local Universe, determined from the Lick Observatory Supernova Search (LOSS). We have obtained 2.3 million…
The nuclear spectrum of M87 covering the Ly_a-H_a wavelength range was obtained with the HST Faint Object Spectrograph (FOS) trough a 0.21 arcsec aperture. Contrary to some previous claims, a single power law (F(nu)~nu^(-a)) can not…
We report combined optical and X-ray observations of nova M31N 2007-12b. Optical spectroscopy obtained 5 days after the 2007 December outburst shows evidence of very high ejection velocities (FWHM H$\alpha \simeq 4500$ km s$^{-1}$). In…
We have measured the line-of-sight velocity distribution from integrated stellar light at two points in the outer halo of M87 (NGC 4486), the second-rank galaxy in the Virgo Cluster. The data were taken at R = 480" ($\sim 41.5$ kpc) and R =…
Very fast novae are novae which evolve exceptionally quickly (on timescales of only days). Due to their rapid evolution, very fast novae are challenging to detect and study, especially at early times. Here we report the discovery, which was…
We report the results of a survey for novae in and between the galaxies of the Fornax cluster. Our survey provides strong evidence that intracluster novae exist and that they provide a useful, independent measure of the intracluster light…
We present our wide field Halpha+N[II] observations of 15 cataclysmic variables to search for remnant nova shells. Such shells have been found around other cataclysmic variables that were hitherto not known as novae. Our candidates were…
M87 is the only known non blazar radio galaxy to emit very high energy (VHE) gamma-rays. During a monitoring program of M87, a rapid flare in VHE gamma-rays was detected by the MAGIC telescope in early 2008. The flux was found to be…
The radio galaxy M87 is well known for its jet, which features a series of bright knots observable from radio to X-ray wavelengths. We analyze the X-ray image and flux variability of the knot HST-1 in the jet. Our analysis includes all 112…
V745 Sco is a Galactic symbiotic recurrent nova with nova eruptions in 1937, 1989 and 2014. We study the behavior of V745 Sco at radio wavelengths (0.6-37,GHz), covering both its 1989 and 2014 eruptions and informed by optical, X-ray, and…
We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular…
Young supernova remnants (SNRs) provide a unique perspective on supernova (SN) progenitors and connect the late evolution of SNe with the onset of the SNR phase. Here we study SN 1885A and G1.9+0.3, the most recent thermonuclear SNe in the…
The nova M31N 2023-11f (2023yoa) has been recently identified as the second eruption of a previously recognized nova, M31N 2013-10c, establishing the latter object as the 21st recurrent nova system thus far identified in M31. Here we…
The recurrent nova M31N 2008-12a experiences annual eruptions, contains a near-Chandrasekhar mass white dwarf, and has the largest mass accretion rate in any nova system. In this paper, we present Hubble Space Telescope (HST) WFC3/UVIS…
We describe a maximum-likelihood method for determining the mass distribution in spherical stellar systems from the radial velocities of a population of discrete test particles. The method assumes a parametric form for the mass distribution…
We use different assumptions for the combination of dust extinction and star formation up to redshifts z >= 5, as well as detailed modeling of supernova properties, to estimate the number of supernovae that should be observable with various…
Many spiral galaxies have extended outer H~I disks and display low levels of star formation, inferred from the far-ultraviolet emission detected by {\it GALEX}, well beyond the optical radius. Here, we investigate the supernova (SN) rate in…
V2487 Ophiuchi (V2487 Oph) is a recurrent nova with classical nova eruptions in 1900 and 1998, and it is also the most extreme known superflare star. These superflares are roughly-hour-long flares with amplitudes and optical energies…