Search Publications

Selection of Compton-thick AGN from a hard photometric sample using XMM-Newton observations

Guainazzi, Matteo; Mostafa, Reham; Ibrahim, Alaa

We present a selection technique to detect Compton-thick (CT) active galactic nuclei (AGNs) in the 3XMM/SDSS-DR7 cross-correlation. A subsample of 3481 X-ray sources that are detected in the hard band (2-8 keV) and have photometric redshifts constitute our parent sample. We first applied an automated spectral-fitting procedure to select highly abs…

HST proper motions on the far side of the Galactic bar-data

Clarkson, William I.; Rich, R. Michael; Kunder, Andrea +10 more

This is the third paper in a series that attempts to observe a clear signature of the Galactic bar/bulge using kinematic observations of the bulge stellar populations in low foreground extinction windows. We report on the detection of ~100 000 new proper motions in four fields covering the far side of the Galactic bar/bulge, at negative longitudes…

Restoration of T80-S telescope's images using neural networks

Roth, Martin M.; Bernardi, Rafael L.; Berdja, Amokrane +2 more

Convolutional neural networks (CNNs) have been used for a wide range of applications in astronomy, including for the restoration of degraded images using a spatially invariant point spread function (PSF) across the field of view. Most existing development techniques use a single PSF in the deconvolution process, which is unrealistic when spatially…

HIP 67506 C: MagAO-X confirmation of a new low-mass stellar companion to HIP 67506 A

Weinberger, Alycia J.; Guyon, Olivier; Close, Laird M. +17 more

We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2λ/D (240 mas) in L^' in MagAO/Clio imaging using the binary differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric accele…

The JCMT nearby galaxies legacy survey: SCUBA-2 observations of nearby galaxies

Pattle, Kate; Gear, Walter; Wilson, Christine D.

We present 850 $\mu$m observations of a sample of 8 nearby spiral galaxies, made using the SCUBA-2 camera on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT Nearby Galaxies Legacy Survey (NGLS). We corrected our data for the presence of the ¹²CO J = 3 → 2 line in the SCUBA-2 850 $\mu$m bandwidth using NGLS HARP data, findin…

Correction to: Spectroscopic follow-up of black hole and neutron star candidates in ellipsoidal variables from Gaia DR3

El-Badry, Kareem; Nagarajan, Pranav; Rodriguez, Antonio C. +2 more

A low-mass hub-filament with double centre revealed in NGC 2071-North

Shimajiri, Y.; Palmeirim, P.; Könyves, Vera +2 more

We present the first analysis in NGC 2071-North as a resolved hub-filament featuring a double centre. This ~1.5 × 1.5 pc² scale filament hub contains ~500 M_⊙. Seen from Planck, magnetic field lines may have facilitated the gathering of material at this isolated location. The energy balance analysis, supported by infalling gas…

Study of the radial dependence of Forbush decreases at 0.28-1 au using data from the Helios 1 and 2 spacecraft

Papaioannou, Athanasios; Richardson, Ian G.; Belov, Anatoly +4 more

We identify and investigate cosmic ray Forbush decreases (FDs) observed in the E > 50 MeV data from the Helios 1 and 2 spacecraft, spanning from 1974-1985 and covering heliocentric distances in the range 0.28-1 au. A Helios FD catalogue is compiled, including the characteristics of the cosmic ray variations, as well as those of the solar wind (…

A simple linear model to aid in analyses of the β Pictoris moving group

Barbosa, Valmir C.; do Nascimento, Josina O.

We build a 4D linear model of object membership in the $\beta$ Pictoris moving group (BPMG), using two nested applications of Principal Component Analysis (PCA) for ~1.5 million objects with high-quality data. These data consist of 3D-Galactic space velocities and Gaia G magnitudes. Through PCA, they ultimately result in a 4D straight line, referr…

The Calar Alto CAFOS direct imaging first data release

Cortés-Contreras, M.; Solano, E.; Rodrigo, C. +3 more

We present the first release of the Calar Alto CAFOS direct imaging data, a project led by the Spanish Virtual Observatory with the goal of enhancing the use of the Calar Alto archive by the astrophysics community. Data Release 1 contains 23 903 reduced and astrometrically calibrated images taken from 2008 March to 2019 July with a median of the m…