Related papers: M31-RV evolution and its alleged multi-outburst pa…

The Andromeda Galaxy (M31) is an object of ongoing study with the Ultraviolet Imaging Telescope (UVIT) on AstroSat. UVIT FUV and NUV photometry is carried out here for a set of 239 clusters in the NE disk and bulge of M31 which overlap with…

Classical novae are quite frequent in M~31. However, very few spectra of M31 novae have been studied to date, especially during the early decline phase. Our aim is to study the photometric and spectral evolution of a M31 nova event close to…

We present the first X-ray and UV/optical observations of a very bright and fast nova in the disc of M31, M31N 2013-01b. The nova reached a peak magnitude $R\sim$15 mag and decayed by 2 magnitudes in only 3 days, making it one of the…

We report $R_cI_c$ light curves of 2 novae in the M31 galaxy which were detected in the four year Nainital Microlensing Survey. One of these novae has been tracked from the initial increase in flux while other has been observed during its…

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…

We have examined the star formation history (SFH) of Andromeda VII (And VII), the brightest and most massive dwarf spheroidal (dSph) satellite of the Andromeda galaxy (M 31). Although M 31 is surrounded by several dSph companions with old…

Extremely luminous, red eruptive variables like RV in M31 are being suggested as exemplars of a new class of astrophysical object. Our greatly extended series of nova simulations shows that classical nova models can produce very red,…

As galaxies evolve, they must enrich and exchange gas with the surrounding medium, but the timing of these processes and how much gas is involved remain poorly understood. In this work, we leverage metals as tracers of past gas flows to…

In our preceding paper, Liverpool Telescope data of M31 novae in eruption were used to facilitate a search for their progenitor systems within archival Hubble Space Telescope (HST) data, with the aim of detecting systems with red giant…

We present evidence for a metal-poor, [Fe/H]$\sim-1.4$ $\sigma$=0.2 dex, stellar halo component detectable at radii from 10 kpc to 70 kpc, in our nearest giant spiral neighbor, the Andromeda galaxy. This metal-poor sample underlies the…

The M 31 nova M31N 2008-12a was recently found to be a recurrent nova (RN) with a recurrence time of about 1 year. This is by far the fastest recurrence time scale of any known RNe. Our optical monitoring programme detected the predicted…

A new, 2.8 deg^2 J,H,K_s infrared survey from the 2MASS 6x program across the extent of the optical disk of the Andromeda (M31) galaxy provides a clear view of the M31 center almost completely unfettered by dust extinction, and reveals a…

We present the discovery of an inhomogenous, low-surface brightness, extended disk-like structure around the Andromeda galaxy (M31) based on a large kinematic survey of more than 2800 stars with the Keck/DEIMOS spectrograph. The stellar…

We map the star formation history across M31 by fitting stellar evolution models to color-magnitude diagrams of each 83$''{\times}$83$''$ (0.3$\times$1.4 kpc, deprojected) region of the PHAT survey outside of the innermost 6$'{\times}$12$'$…

Here we report that the most rapidly recurring nova, M31N 2008-12a, which erupts annually, is surrounded by a "nova super-remnant" which demonstrates that M31N 2008-12a has erupted with high frequency for millions of years.

We analyzed the available LIGO data coincident with GRB 070201, a short duration hard spectrum gamma-ray burst whose electromagnetically determined sky position is coincident with the spiral arms of the Andromeda galaxy (M31). Possible…

2 years worth of archival FERMI-LAT data was used to search for the gamma-ray emission from the Andromeda galaxy. The data show no noticeable elliptical image. Subsequent on-off source aperture photometry analysis using a CO image template…

We present the first detailed spectroscopic and photometric analysis of an eclipsing binary in the Andromeda Galaxy (M31). This is a 19.3-mag semi-detached system with components of late-O and early-B spectral types. From the light and…

The nearest giant spiral, M31, exhibits a kinematically hot stellar disc, a global star formation episode ~2-4 Gyr ago, and conspicuous substructures in its stellar halo that are suggestive of a recent accretion event. Recent chemodynamical…

We present images and a color-magnitude diagram for And V, a new dwarf spheroidal companion to M31 that was found using a digital filtering technique applied to 1550 square degrees of the second Palomar Sky Survey. And V resolves into stars…