Related papers: Modelling the ArH$^+$ emission from the Crab Nebul…
We report on observations of the polarization of optical and {\gamma}-ray photons from the Crab nebula and pulsar system using the Galway Astronomical Stokes Polarimeter (GASP), the Hubble Space Telescope/Advanced Camera for Surveys…
Long-term measurements have been carried out of the Crab Nebula radio emission flux density relative to Orion A at 927 MHz and relative to Cygnus A and Virgo A at 151.5 MHz. As a result the mean rates have been found of the secular change…
The Crab nebula and its pulsar have been observed for about 3 hours with the high-speed photo-polarimeter OPTIMA in January 2002 at the Calar Alto 3.5m telescope. The Crab pulsar intensity and polarization are determined at all phases of…
The remarkable Crab Nebula is powered by an energetic pulsar whose relativistic wind interacts with the inner parts of the Supernova Remnant SN1054. Despite low-intensity optical and X-ray variations in the inner Nebula, the Crab has been…
The Crab Nebula is used by many instruments as a calibration source, in particular at high energy, where it is one of the brightest celestial object. The spectrometer INTEGRAL SPI (20 keV - 8 MeV), in operation since October 2002, offers a…
A significant fraction of the molecular gas in star-forming regions is irradiated by stellar UV photons. In these environments, the electron density (n_e) plays a critical role in the gas dynamics, chemistry, and collisional excitation of…
We have analyzed five ROSAT HRI images of the Crab Nebula spanning the years 1991 to 1997 and have found significant changes in the emission structure of the X-ray torus surrounding the pulsar. Certain regions increase in brightness by…
The $\rho$ Oph molecular cloud is one of the best examples of spinning dust emission, first detected by the Cosmic Background Imager (CBI). Here we present 4.5 arcmin observations with CBI 2 that confirm 31 GHz emission from $\rho$ Oph W,…
This study presents optical and near-infrared photometric observations, alongside mid-infrared spectroscopic data from the ISO SWS instrument, to examine potential correlations between Aromatic Infrared Band (AIB) features and the optical…
The unusually short durations, high luminosities, and high photon energies of the Crab Nebula gamma-ray flares require relativistic bulk motion of the emitting plasma. We explain the Crab flares as the result of randomly oriented…
The {\gamma}-ray flares from the Crab nebula observed by AGILE and Fermi-LAT reaching GeV energies and lasting several days challenge the standard models for particle acceleration in pulsar wind nebulae, because the radiating electrons have…
Additional high-frequency components of the pulsar radiation in Crab Nebula are considered as a result of the resonance with the surface electromagnetic wave at nonlinear reflection from of the neutron star surface.This stimulated…
A model of an accelerated expansion of the Crab Nebula powered by the spinning-down Crab pulsar is proposed, in which time dependence of the acceleration is connected with evolution of pulsar luminosity. Using recent observational data, we…
We report on the extremely intense and fast gamma-ray are above 100 MeV detected by AGILE from the Crab Nebula in mid-April 2011. This event is the fourth of a sequence of reported major gamma-ray flares produced by the Crab Nebula in the…
Gamma rays with energies greater than 7 TeV from the Crab pulsar/nebula have been observed at large zenith angles, using the Imaging Atmospheric Technique from Woomera, South Australia. CANGAROO data taken in 1992, 1993 and 1995 indicate…
We discuss the detection of 14 rovibrational lines of CH$^+$, obtained with the iSHELL spectrograph on NASA's Infrared Telescope Facility (IRTF) on Maunakea. Our observations in the 3.49 - 4.13 $\mu$m spectral region, obtained with a 0.375"…
High resolution infrared imaging observations of the young Planetary Nebulae NGC 7027 and BD +303639, taken with the newly installed TIFR Infrared Camera-II (TIRCAM2) on 3.6m Devasthal Optical Telescope (DOT), ARIES, Nainital, are being…
We present a sample of resolved galactic HII regions and photodissociation regions (PDRs) observed with the Spitzer infrared spectrograph (IRS) in spectral mapping mode between the wavelengths of 5--15 $\mu$m. For each object we have…
We report on a bright flare in the Crab Nebula detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The period of significantly increased luminosity occurred in 2013 March and lasted for approximately 2…
What sort of supernova gave rise to the Crab Nebula? There are several indications that the Crab arose from a sub-energetic explosion of an 8-10 Msun star, this appears to conflict with the high luminosity indicated by historical…