Fast Radio Bursts seen by ASKAP
The Australian Square Kilometre Array Pathfinder (ASKAP) has started operations and immediately detected three Fast Radio Bursts (FRBs). With only ~30 FRBs detected so far and over several years, detecting 3 new ones within a few days promises a wealth of observations in the future. For the moment the bursts have 'only' been detected in the primary beam of the telescopes (see figure below), but once interferometry between several telescopes pointing in the same direction is used, the pointing accuracy will improve to arcsecond levels. The paper describing one of the detected FRBs can be found here. A summary is also given in this nice article.
Hopefully ASKAP (and later SKA) will be able to detect the burst during observations and emit online alerts to follow-up instruments. I am already looking forward to extending the H.E.S.S. FRB program from Parkes to SKA/ASKAP alerts. See FRB follow-up with H.E.S.S. for details about my recent work on this.
Radio image of the sky where ASKAP found its first FRB. The blue circles are the 36 patches of the sky that ASKAP antenna number 5 was watching at the time the FRB was detected. The red smudge marks where the FRB came from. The black dots are galaxies. The full Moon is shown to scale, in the bottom corner. Ian Heywood (CSIRO), from The Conversation
XMM-Newton slew catalog
Astronomical instruments are expensive. Satellites are even more expensive. Optimizing the data taking and making the most out of the available observations is therefore an important process. The XMM-Newton X-ray satellite has illustrated this by publishing its second "Second Slew Survey Catalog". Typically ground and space borne observatories perform pointed observations of a pre-defined list of interesting regions and objects. The time spent moving the instrument from one direction to the next is usually called dead-time and disregarded. The ESA led XMM-Newton satellite continues data taking during the slewing and the team managed to carefully analyse the obtained data and extract very useful information. The resulting source catalog contains ~70.000 sources detected during the slewing and represents ~10% of all XMM detected sources. The analysis add data to some old friends of mine: star-and-black hole binary systems like GRS 1915+105 and V 4641 Sgr (see Microquasars for a recent H.E.S.S./RXTE analysis of these objects).
Sidenote: The operation mode of current TeV gamma-ray Cherenkov telescopes does not allow for data taking during slewing (the cameras are switched off in order to prevent damage due to bright stars passing through the field-of-view). On the other hand, the upcoming Cherenkov Telescope Array (CTA) will be able to continuously take data and one can imaging a future "CTA Slew Survey Catalog"...
New view of the Crab Nebula
Combining data from various observatories covering (almost) the full electromagnetic spectrum, a new, very detailed and beautiful image of the Crab Nebula has been produced. See the NASA website for details. The individual ingredients are highlighted in the video below:
This video starts with a composite image of the Crab Nebula, a supernova remnant that was assembled by combining data from five telescopes spanning nearly the entire breadth of the electromagnetic spectrum: the Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory. The video dissolves to the red-colored radio-light view that shows how a neutron star’s fierce “wind” of charged particles from the central neutron star energized the nebula, causing it to emit the radio waves. The yellow-colored infrared image includes the glow of dust particles absorbing ultraviolet and visible light. The green-colored Hubble visible-light image offers a very sharp view of hot filamentary structures that permeate this nebula. The blue-colored ultraviolet image and the purple-colored X-ray image shows the effect of an energetic cloud of electrons driven by a rapidly rotating neutron star at the center of the nebula. Credits: NASA, ESA, J. DePasquale (STScI)
The Crab Nebula was the first astrophysical object observed in TeV gamma-rays. This breakthrough measurement was performed with the Whipple Observatory (using a 10-meter mirror and a 37-pixel camera) and was announced in July 1989 ("Observation of TeV gamma rays from the Crab nebula using the atmospheric Cerenkov imaging technique" – APJ 342 (1989) 379-395). Until today the Crab nebula is used as 'standard candle' and calibration source in high-energy gamma-ray astronomy. A recent example can be found in this paper from the HAWC Collaboration: Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory.