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Classical T-Tauri stars with VPHAS+: II: NGC 6383 in Sh 2-012
Kalari, V. M.
This paper presents optical (ugriHα)-infrared (JHKs, 3.6-8.0 µm) photometry and Gaia astrometry of 55 Classical T-Tauri stars (CTTS) in the star-forming region Sh 2-012 and its central cluster NGC 6383. The sample was identified based on photometric Hα emission linewidths, and has a median age of 2.8 ± 1.6 Myr, with a mass range between 0.3 …
X-ray properties of two transient ULX candidates in galaxy NGC 7090
O'Brien, P. T.; Osborne, J. P.; Page, K. L. +2 more
We report the X-ray data analysis of two transient ultraluminous X-ray sources (ULXs; hereafter X1 and X2) located in the nearby galaxy NGC 7090. While they were not detected in the 2004 XMM-Newton and 2005 Chandra observations, their 0.3-10 keV X-ray luminosities reached >3 × 1039 erg s-1in later XMM-Newton or Swift obser…
Nuclear spallation in active galaxies
Reynolds, C. S.; Gallo, L. C.; García, J. A. +3 more
A number of works point to the presence of narrow emission features at unusual energies in the X-ray spectra of active galactic nuclei or to potentially low iron abundances as possible evidence for the spallation of iron. With the imminence of high-resolution calorimeter spectroscopy, the potential to test spallation models in astrophysical source…
Unveiling the 100 pc scale nuclear radio structure of NGC 6217 with e-MERLIN and the VLA
Muxlow, T. W. B.; Argo, M. K.; Knapen, J. H. +13 more
We present high-sensitivity 1.51 GHz e-MERLIN (e-Multi-Element Radio-Linked Interferometer Network) radio images of the nearby galaxy NGC 6217. We resolve the compact radio source at the centre of NGC 6217 for the first time, finding a twin-lobed structure with a total linear size of ∼4 arcsec (∼400 pc). The radio source does not have a compact ce…
X-ray studies of the gamma-ray pulsar J1826-1256 and its pulsar wind nebula with Chandra and XMM-Newton
Karpova, Anna V.; Zyuzin, Dmitry A.; Shibanov, Yuriy A.
We have analysed archival XMM-Newton and Chandra observations of the γ-ray radio-quiet pulsar J1826-1256 and its pulsar wind nebula. The pulsar spectrum can be described by a power-law model with photon index Γ ≈ 1. We find that the nebular spectrum softens with increasing distance from the pulsar, implying synchrotron cooling. The empirical inter…
New hot subdwarf variables from the EC survey
Kilkenny, D.; Lynas-Gray, A. E.; Worters, H. L.
We present new results for hot subdwarf stars from the Edinburgh-Cape (EC) blue object survey. EC 03089-6421, an sdO star recently discovered to be a very rapid pulsator with periods near 31.1 and 34.2 s (29.2 and 32.1 mHz), is shown to have an even faster pulsation near 26.6 s (37.6 mHz) although all pulsations are variable in amplitude and effec…
The radial distribution of blue stragglers in Galactic globular cluster NGC 6656 - clues to the dynamical status
Yadav, R. K. S.; Singh, Gaurav
We present the dynamical status of the Galactic globular cluster NGC 6656 using the spatial distribution of blue straggler stars (BSSs). A combination of multi-wavelength high-resolution space- and ground-based data are used to cover a large cluster region. We determine the centre of gravity (Cgrav) and construct the projected density p…
Soft excess in the quiescent Be/X-ray pulsar RX J0812.4-3114
Ho, Wynn C. G.; Potekhin, Alexander Y.; Heinke, Craig O. +3 more
We report a 72 ks XMM-Newton observation of the Be/X-ray pulsar (BeXRP) RX J0812.4-3114 in quiescence (L_X ≈ 1.6× 10^{33} erg s^{-1}). Intriguingly, we find a two-component spectrum, with a hard power-law (Γ ≈ 1.5) and a soft blackbody-like excess below ≈1 keV. The blackbody component is consistent in kT with a prior quiescent Chandra observation …
Progressive steepening of the SNR RX J1713.7-3946 X-ray spectrum from XMM-Newton to INTEGRAL
Churazov, Eugene; Krivonos, Roman; Kuznetsova, Ekaterina +2 more
In this work, we present the first detailed analysis of the supernova remnant RX J1713.7-3946 in the hard X-ray energy range with the Imager on Board the INTEGRAL Satellite (IBIS) coded-mask telescope onboard the INTEGRAL observatory. The shell-type morphology of the entire remnant is mapped in hard X-rays for the first time and significantly dete…
Gemini IFU, VLA, and HST observations of the OH Megamaser Galaxy IRAS17526 + 3253
Storchi-Bergmann, T.; Robinson, A.; Riffel, R. A. +7 more
We present a multiwavelength study of the OH megamaser galaxy IRAS17526 + 3253, based on new Gemini multi-object spectrograph integral field unit (GMOS/IFU) observations, Hubble Space Telescope F814W, and H α + [N II] images, and archival 2MASS and 1.49 GHz VLA data. The Hubble Space Telescope(HST) images clearly reveal a mid-to-advanced stage maj…