Related papers: A bright X-ray transient towards NGC 5128 (Centaur…
Centaurus A (Cen A) is a bright radio source associated with the nearby galaxy NGC 5128 where high-resolution radio observations can probe the jet at scales of less than a light-day. The South Pole Telescope (SPT) and the Atacama Pathfinder…
After a quarter of a century of gamma-ray burst (GRB) astronomy, the Italian-Dutch satellite BeppoSAX on Feb 28th, 1997 detected a soft X-ray afterglow from GRB 970228 and positioned it accurately. This made possible the successful…
1WGA J1346.5-6255 is a ROSAT X-ray source found within the radio lobes of the supernova remnant (SNR) G309.2-00.6. This source also appears to coincide with the bright and early-type star HD 119682, which is in the middle of the galactic…
We report the optical identifications of two X-ray luminous point sources in the spiral galaxy NGC4565 based on archive data of Chandra and the Hubble Space Telescope. The central X-ray point source, RXJ1236.3+2559, is found to be the…
We present X-ray and optical observations of a new transient X-ray source in M31 first detected 23-May-2004 at R.A.=00:43:09.940 +/- 0.65'', Dec.=41:23:32.49 +/- 0.66''. The X-ray lightcurve shows two peaks separated by several months,…
We present the results of X-ray observations of four bright transients sources detected in the July 2004 XMM-Newton observations of the central bulge of M31. Two X-ray sources, XMMU J004315.5+412440 and XMMU J004144.7+411110, were…
We present the results from INTEGRAL and Swift/XRT observations of the hitherto poorly studied unidentified X-ray transient AX J1949.8+2534, and on archival multiwavelength observations of field objects. Bright hard X-ray outbursts have…
Using a very deep observation with HST/STIS, we have searched for an optical counterpart to the nearby radio-quiet isolated neutron star RX J1308.6+2127 (RBS 1223). We have identified a single object in the 90% Chandra error circle that we…
The globular cluster NGC 6440 is known to harbor a bright neutron-star X-ray transient. We observed the globular cluster with Chandra on two occasions when the bright transient was in its quiescent state in July 2000 and June 2003 (both…
The nearby barred spiral galaxy NGC 1672 is thought to have a weak Seyfert nucleus in addition to its strong starburst activity. Observations with the PSPC and HRI instruments on board the ROSAT X-ray satellite show that three X-ray sources…
The transient X-ray source SAX J1810.8-2609 was discovered on 1998, March 10 with the Wide Field Cameras on board the BeppoSAX satellite, while observing the Galactic Bulge in the 2-28 keV energy range. On March 11, a strong type-I X-ray…
We report the discovery of a ultraluminous X-ray source (ULX; CXO J133815.6+043255) in NGC 5252. This ULX is an off-nuclear point-source, which is 22$^{\prime\prime}$ away from the center of NGC 5252, and has an X-ray luminosity of 1.5…
Two X-ray bright early type galaxies, selected for their unusually high X-ray to optical flux ratio, have been observed at high spatial resolution with the ROSAT HRI. Both sources are clearly extended (more than 250 kpc in radius), thus…
I report the discovery of a transient broad-H$\alpha$ point source in the outskirts of the giant elliptical galaxy NGC 1404, discovered in archival observations taken with the MUSE integral field spectrograph. The H$\alpha$ line width of…
A Chandra X-Ray Observatory ACIS-S imaging observation is used to study the population of X-ray sources in the nearby Sab galaxy M81 (NGC 3031). A total of 177 sources are detected with 124 located within the D25 isophote to a limiting…
The radio sky is poorly sampled for rapidly varying transients because of the narrow field-of-view of most imaging radio telescopes at cm and shorter wavelengths. The emergence of sensitive long wavelength observations with intrinsically…
We report the discovery of a flaring X-ray source with an optical counterpart with Halpha emission and red-excess, in the direction of the SMC. A 100 ksec X-ray observation with Chandra detected a flare lasting 6 ksec in the source CXO…
We report discovery of a compact object at high Galactic latitude. The object was initially identified as a ROSAT All-Sky Survey Bright Source Catalog X-ray source, 1RXS J141256.0+792204, statistically likely to possess a high X-ray to…
We report the detection of a transient $\gamma$-ray source in the direction of B3 1428+422 ($z=4.72$) by analyzing the 110-month {\it Fermi}-LAT Pass 8 data. The new transient $\gamma-$ray source is far away from the Galactic plane and has…
We report the discovery of a remarkable gamma-ray transient source near the Galactic plane, GRO J1838-04. This source was serendipitously discovered by EGRET in June 1995 with a peak intensity of 4 E(-6) ph/cm/cm/s (for photon energies…