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We present new high and low resolution spectroscopic and photometric data of nine members of the young association CMa R1. All the stars have circumstellar dust at some distance as could be expected from their association with reflection…

We report on an unusual radio source J180526-292953, initially identified as a steep spectrum, polarized point source toward the Galactic bulge and found to coincide with the nearby K dwarf HD317101A. We conducted a multi-wavelength radio…

[Abridged] As part of our on-going investigation of magnetic activity in ultracool dwarfs we present simultaneous radio, X-ray, UV, and optical observations of LSR1835+32 (M8.5), and simultaneous X-ray and UV observations of VB10 (M8), both…

We have used phase-resolved high-resolution images and low resolution spectra taken at the ESO Very Large Telescope, to study the properties of the low-mass Helium White Dwarf companion to the millisecond pulsar \psr (hereafter COM…

Astrophysics · Physics 2009-11-11 G. Cocozza , F. R. Ferraro , A. Possenti , N. D'Amico

According to activity-rotation relations, rapid rotators are expected to show high levels of magnetic activity. However, recent studies with TESS have found Ultra Fast Rotating (UFR) M dwarfs with periods $<1$ d displaying low levels of…

Solar and Stellar Astrophysics · Physics 2026-04-10 Lauren Doyle , George W. King , Gavin Ramsay , Lía R. Corrales , Stefano Bagnulo , J. Gerry Doyle , Pasi Hakala

We have used deep high-resolution multiband images taken at the ESO Very Large Telescope to identify the optical binary companion to the millisecond pulsar (PSR J1911-5958A) located in the halo of the Galactic Globular Cluster NGC6752. The…

Astrophysics · Physics 2009-11-10 Francesco R. Ferraro , Andrea Possenti , Elena Sabbi , Nichi D'Amico

In this paper we analyze the kinematics, chemistry, and physical properties of a sample of the most metal-poor damped Lyman-alpha systems (DLAs), to uncover their links to modern-day galaxies. We present evidence that the DLA population as…

Astrophysics of Galaxies · Physics 2015-08-04 Ryan Cooke , Max Pettini , Regina A. Jorgenson

We present new upper limits on the neutral hydrogen (HI) content within the stellar half-light ellipses of 15 Galactic dwarf spheroidal galaxies (dSphs), derived from pointed observations with the Green Bank Telescope (GBT) as well as…

Astrophysics of Galaxies · Physics 2015-06-23 K. Spekkens , N. Urbancic , B. S. Mason , B. Willman , J. E. Aguirre

We investigated almost 500 stars distributed among 193 binary or multiple systems made of late-F, G-, or early-K primaries and late-K or M dwarf companion candidates. For all of them, we compiled or measured coordinates, J-band magnitudes,…

We have obtained optical spectra of seven stars in the old galactic cluster M67 that are unusual sources of X-rays, and investigate whether the X-ray emission is due to magnetic activity or to mass transfer. The two binaries below the giant…

Astrophysics · Physics 2007-05-23 Maureen van den Berg , Frank Verbunt , Robert D. Mathieu

We explore the H-alpha emission in the massive quiescent galaxies observed by the KMOS-3D survey at 0.7 < z < 2.7. The H-alpha line is robustly detected in 20 out of 120 UVJ-selected quiescent galaxies, and we classify the emission…

Hot subdwarfs (sdO/Bs) are the helium-burning cores of red giants, which lost almost all of their hydrogen envelopes. This mass loss is often triggered by common envelope interactions with close stellar or even substellar companions. Cool…

Solar and Stellar Astrophysics · Physics 2018-06-20 V. Schaffenroth , S. Geier , U. Heber , R. Gerber , D. Schneider , E. Ziegerer , O. Cordes

The properties of 2M1207b, a young (~ 8 Myr) planet-mass companion, have lacked a satisfactory explanation for some time. The combination of low luminosity, red near-IR colors, and L-type near-IR spectrum (previously consistent with Teff ~…

Solar and Stellar Astrophysics · Physics 2015-05-28 Travis S. Barman , Bruce Macintosh , Quinn M. Konopacky , Christian Marois

We present a kinematic analysis of 152 low surface gravity M7-L8 dwarfs by adding 8 parallaxes, 38 radial velocities, and 19 proper motions. We find 39 objects to be high-likelihood or bona fide members of nearby moving groups, 92 objects…

An exotic environment surrounds the young stellar groups associated with the Canis Major (CMa) OB1/R1 region, which probably was formed under feedback from at least three supernova events having occurred a few million years ago. We use…

We compare the kinematics of M31's satellite galaxies to the mass profiles of the subhaloes they are expected to inhabit in LCDM. We consider the most massive subhaloes of an approximately M31-sized halo, following the assumption of a…

Astrophysics of Galaxies · Physics 2015-06-19 Erik J. Tollerud , Michael Boylan-Kolchin , James S. Bullock

UCAC2 46706450 is a late-type star with an ultraviolet (UV) excess. It was considered a candidate to establish a sample of FGK stars with white dwarf (WD) companions that can be used to test binary evolution models. To verify the WD nature…

Understanding stellar activity in M dwarfs is fundamental to improving our knowledge of the physics of stellar atmospheres and for planet search programmes. High levels of stellar activity (also with flare events) can cause additional…

Solar and Stellar Astrophysics · Physics 2020-10-07 C. Di Maio , C. Argiroffi , G. Micela , S. Benatti , A. F. Lanza , G. Scandariato , J. Maldonado , A. Maggio , L. Affer , R. Claudi

We present a method to select hot subdwarf stars with A to M-type companions using photometric selection criteria. We cover a wide range in wavelength by combining GALEX ultraviolet data, optical photometry from the SDSS and the Carlsberg…

Solar and Stellar Astrophysics · Physics 2015-06-05 J. Girven , D. Steeghs , U. Heber , B. T. Gänsicke , T. R. Marsh , E. Breedt , C. M. Copperwheat , S. Pyrzas , P. Longa Peña