Related papers: A search for cool molecular gas in GK Persei and o…
The eruption of Nova Persei 1901 (GK Per) occurred 125 yrs ago; remarkably it still holds major surprises. Using data from the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx), we find…
I present the data of the shell of classical Nova Persei (1901) obtained by the Advanced CCD Imaging Spectrometer S3 detector on-board \cha Observatory. The X-ray nebula is affected mostly by the complex interstellar medium around the nova…
Classical nova eruptions result from thermonuclear-powered runaways in, and ejection of, the hydrogen-rich envelopes of white dwarf stars accreted from their close binary companions. Novae brighten to up to 1,000,000 solar luminosities, and…
Most old supernova remnants (SNRs) in the Milky Way have not yet been identified. Considering their large potential number and the sufficient momentum-energy transfer to the interstellar medium (ISM), they are a key part of our…
Red novae are optical transients erupting at luminosities typically higher than those of classical novae. Their outbursts are believed to be caused by stellar mergers. We present millimeter/submillimeter-wave observations with ALMA and SMA…
We present our recent results on mm-wave CO observations of proto-planetary nebulae. These include high-resolution interferometric maps of various CO lines in three well known bipolar PPNe: M1-92, M2-56 and OH231.8+4.2. The global…
We present 1.2 mm continuum images and spectral line observations of CO(1--0) and SiO(3--2) rotational transitions of the recent nova V4743 Sgr. The nova is detected at 1.2 mm showing a variable millimetre emission. Only upper limits of…
We have imaged the ejecta of GK Persei (Nova Persei 1901 A.D.) with the Hubble Space Telescope (HST), revealing hundreds of cometary-like structures. One or both ends of the structures often show a brightness enhancement relative to the…
We report the results of a sensitive survey of young planetary nebulae in the CO J=2-1 line that significantly increases the available data on warm, dense, molecular gas in the early phases of planetary nebula formation. The observations…
Cold molecular gas has recently been found is several cooling flow clusters cores with single dish telescopes. High spatial resolution imaging of some of these clusters then revealed the peculiar morphology and dynamics of the CO emission…
We present a kinematical study of the optical ejecta of GK Per. It is based on proper motions measurements of 282 knots from ~20 images spanning 25 years. Doppler-shifts are also computed for 217 knots. The combination of proper motions and…
We have recently detected CO lines in the well-known filaments around NGC 1275, the galaxy at the centre of the Perseus cluster of galaxies. These previous observations, with the HERA multi-beam array at the IRAM 30m telescope enabled us to…
We report the detection of carbon monoxide (CO) emission from the young supernova remnant Cassiopeia A (Cas A) at wavelengths corresponding to the fundamental vibrational mode at 4.65 micron. We obtained AKARI Infrared Camera spectra…
Classical novae are potential gamma-ray emitters, both in lines and in a continuum. Continuum emission (at energies between 20-30 and 511 keV) and line emission at 511 keV are related to positron annihilation and its Comptonization in the…
We present new observations of the nebular remnant of the old nova GK Persei 1901, in the optical using the 2m HCT and at low radio frequencies using the GMRT. The evolution of the nova remnant indicates shock interaction with the ambient…
We report spectroscopic and imaging observations of rotational transitions of cold CO and SiO in the ejecta of SN1987A, the first such emission detected in a supernova remnant. In addition to line luminosities for the CO J=1-0, 2-1, 6-5,…
Whether or not supernovae contribute significantly to the overall dust budget is a controversial subject. Submillimetre (submm) observations, sensitive to cold dust, have shown an excess at 450 and 850 microns in young remnants Cassiopeia A…
One hundred years after the eruption of GK Per and the detection of oscillations in its light curve it is still unclear why certain novae show a smooth decline in their optical light curves after outburst while others have oscillations /…
GK Persei is an intermediate polar that exhibits a dwarf nova outburst approximately every 1000 days. During previous outbursts the system has displayed kilo-second quasi-periodic oscillations (QPOs) in X-ray emission. These oscillations…
We report the discovery of thermal X-ray emission from the youngest Galactic supernova remnant G1.9+0.3, from a 237-ks Chandra observation. We detect strong K-shell lines of Si, S, Ar, Ca, and Fe. In addition, we detect a 4.1 keV line with…