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We present Very Long Baseline Array (VLBA) observations of the radio source J1625+4134 at 22 and 15 GHz and analyze them in concurrence with other existing VLBI data on this source. The high resolution images at 15 and 22 GHz show a short…
This paper presents high-resolution ALMA observations of the massive young stellar object G25.65+1.05, which is known to host water maser super flares. To investigate the nature of compact continuum sources that have been previously…
15 VLBA observations of the BL Lac object 0716+714, performed between 1994.67 and 2006.40 at 15 GHz, have been analyzed. Part of the data (12 epochs) were obtained within the Mojave-survey project and reanalyzed by us. We present a new…
We present multi-frequency Very Long Baseline Array (VLBA) follow-up observations of VLBA Imaging and Polarimetry Survey sources identified as likely compact symmetric objects (CSOs) or super-massive binary black holes (SBBHs). We also…
We have carried out an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115, using the Megasecond Chandra X-Ray Visionary Project observation (total exposure time 1.1 Ms). In total we found 136…
We present results of multifrequency polarimetric VLBA observations of 34 compact radio sources. The observations are part of a large survey undertaken to identify CSOs Observed in the Northern Sky (COINS). Compact Symmetric Objects (CSOs)…
Compact symmetric objects (CSOs) are thought to be short-lived radio sources with two lobes of emission that are separated by less than a kpc in projection. However, studies of such systems at high redshift is challenging due to the limited…
The nucleus of M81 was observed at 8.3 GHz with VLBI at 20 epochs over 4.5yrs, with a linear resolution at the source of about 2000 AU or 0.01 pc. Phase-referenced mapping with respect to the geometric center of supernova 1993J enabled us…
Four close radio sources in the International Celestial Reference Frame (ICRF) catalog were observed using phase referencing with the VLBA at 43, 23 and 8.6 GHz, and with VERA at 23 GHz over a one year period. The goal was to determine the…
Here we summarize our results from a detailed multi-frequency study of the QSO 3C309.1 based on the Very Long Baseline Array (VLBA) observations made in mid 1998. From our images, we find a curved jet extending up to 100 milliarcseconds…
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…
The object of this study is one of the most energetic and luminous molecular outflows known in the Galaxy, G331.512-0.103. Observations with ALMA Band 7 (350 GHz; 0.86 mm) reveal a very compact, extremely young bipolar outflow and a more…
We present Giant Metrewave Radio Telescope (GMRT) 240 MHz observations of the nearby luminous FR I radio source 3C 270, in the group-central elliptical NGC 4261. Combining these data with reprocessed Very Large Array (VLA) 1.55 and 4.8 GHz…
Space-VLBI observations of stellar sources represent a challenge since there are few sources with sufficiently high brightness temperature for detection on space-ground baselines. X-ray binaries (XRB) are among the few types of stellar…
We report the detection of a massive (M(gas) > 5x10^9 Msun) molecular/dusty disk of 1.4kpc-size fueling the central engine of the Compact Symmetric Object (CSO) 4C31.04 based on high-resolution (0.5''--1.2'') observations done with the IRAM…
The high-frequency peaked BL Lac object 1ES 0229+200 (z = 0.14) was first detected in very high energy (VHE, E > 100 GeV) $\gamma$-rays by the H.E.S.S. (High Energy Stereoscopic System) collaboration in 2006. No flux variability was…
Multi-epoch GHz Very Long Baseline Interferometry (VLBI) data of the radio-loud quasar J1101+7225 were analyzed to estimate the proper motion of extended optically thin jet components. Two components separated from the core could be mapped…
We report on VLBA observations of a gamma-ray bright blazar NRAO 530 at multiple frequencies (5, 8, 15, 22, 39, 43, and 45 GHz) in 1997 and 1999. These multi-epoch multi-frequency high-resolution VLBI images exhibit a consistent…
We compare recent observations of the supernova remnant G11.2-0.3 taken with the VLA during 2001-02 with images from VLA archives (1984-85) to detect and measure the amount of expansion that has occurred during 17 years. The bright,…
We present a Chandra observation of the candidate BL Lac object EXO 0423.4-0840. The X-ray emission from EXO 0423.4-0840 is clearly extended, and is associated with an optical early-type galaxy, MCG-01-12-005, at the centre of cluster ClG…