Related papers: New data for the LBV in NGC 4736

We present new Chandra observations of the outer halo of the giant elliptical galaxy NGC 4472 (M49) in the Virgo Cluster. The data extend to 130 kpc (28'), and have a combined exposure time of 150 ks. After identifying optical counterparts…

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,…

A recent paper (arXiv:0804.3463) claims that the presence of a soft X-ray component in an X-ray source in NGC 6946 provides strong evidence that its black hole mass is definitely $>100\msun$, and more probably $\sim 400\msun$, even if the…

An increasing number of non-terminal eruptions are being found in the numerous surveys for optical transients. Very little is known about these giant eruptions, their progenitors and their evolutionary state. A greatly improved census of…

We report near-infrared photometry, spectroscopy, and speckle imaging of the hot, luminous star we identify as candidate LBV 1806-20. We also present photometry and spectroscopy of 3 nearby stars, which are members of the same star cluster…

Luminous Blue Variables (LBVs) are massive stars with extreme luminosities, exhibiting significant irregular photometric and spectroscopic variability. This paper is dedicated to the study of dormant LBV Var$\,$2 in the galaxy M33, which…

We report optical and near-infrared spectra of the central star of the radio source G79.29+0.46, a candidate luminous blue variable. The spectra contain numerous narrow (FWHM < 100 km/s emission lines of which the low-lying hydrogen lines…

From a deep multi-epoch Chandra observation of the elliptical galaxy NGC 3379 we report the spectral properties of eight luminous LMXBs (LX>1.2E38 erg/s). We also present a set of spectral simulations, produced to aid the interpretation of…

We present the first photo- and spectropolarimetric observations of the changing-look active galactic nucleus NGC~1346 taken with the Perkins telescope (November 2022, March 2025) and VLT/FORS2 (August and September 2024), which have…

MCA-1B (also called UIT003) is a luminous hot star in the western outskirts of M33, classified over 20yr ago with a spectral type of Ofpe/WN9 and identified then as a candidate luminous blue variable (LBV). Palomar Transient Factory data…

We present BVRI photometry of supernova (SN) 2016coj in NGC 4125 from $9$ days before to $57$ days after its $B$-band maximum light. Our light curves and color curves suggest that this event belongs to the "normal" class of type Ia SNe,…

We present milliarcsecond-resolution radio very long baseline interferometry (VLBI) observations of the ultracool dwarfs TVLM513-46546 (M8.5) and 2MASS J00361617+1821104 (L3.5) in an attempt to detect sub-stellar companions via direct…

We present the analysis of existing optical photometry and new optical spectroscopy of the candidate cataclysmic variable star OGLE-BLG504.12.201843. As was shown previously, this object has an orbital period of 0.523419 days and exhibits…

High-resolution spectra of the LBV candidate Schulte 12 in the Cyg OB2 association were obtained at the 6-meter BTA telescope with the NES echelle spectrograph on the arbitrary dates in 2001-2022. Variability of the emission profile of…

A total of 185 luminous blue variable (LBV) candidates with V < 18.5 and B-V < 0.35 are selected based on the photometrical Survey of Local Group Galaxies made by P. Massey et al. 2006. The candidates were selected using aperture photometry…

We present the variability study of the lowest-luminosity Seyfert 1 galaxy NGC 4395 based on the photometric monitoring campaigns in 2017 and 2018. Using 22 ground-based and space telescopes, we monitored NGC 4395 with a $\sim$5 minute…

We report on sensitive 1.4-GHz VLBI radio observations of the unusually luminous supernova remnant SNR 4449-1 in the galaxy NGC 4449, which gave us the first well-resolved image of this object. The remnant's radio morphology consists of two…

We report on the discovery with Chandra of a strong modulation (~90% pulsed fraction) at ~6.4 h from the source CXOU J123030.3+413853 in the star-forming, low-metallicity spiral galaxy NGC 4490, which is interacting with the irregular…

The recent results from photometric and spectroscopic study of the FUor star V2493 Cyg (HBC 722) are presented in the paper. The outburst of V2493 Cyg was registered during the summer of 2010 before the brightness of the star to reach the…

We present the results of the long-term (20-year period, from 1996 to 2015) optical spectral monitoring of the Seyfert 1 galaxy NGC 7469. The variation in the light-curves of the broad He II {\lambda}4686A H{\beta} and H{\alpha} lines, and…