Bizarre repeating radio signal near galactic center may be brand new object
Astronomers have detected a strange radio source coming from somewhere near the center of the Milky Way galaxy. The signal repeats seemingly at random, and can’t be neatly attributed to any known astronomical object, leading the team to consider that it might be something brand new.
more…
Ya not talkin’ bout ABC Classic FM and them Gergorian Brothers, are ya, hey what but.
Link to paper
GCRT J1742-3001: A NEW RADIO TRANSIENT TOWARD THE GALACTIC CENTER
https://iopscience.iop.org/article/10.1088/0004-637X/696/1/280
Tau.Neutrino said:
Link to paperGCRT J1742-3001: A NEW RADIO TRANSIENT TOWARD THE GALACTIC CENTER
https://iopscience.iop.org/article/10.1088/0004-637X/696/1/280
> Many astronomical sources exhibit transient radio emission including flare stars, brown dwarfs, masers, γ-ray bursts, pulsars, supernovae, active galactic nuclei, and neutron star and black hole X-ray binaries.
My first thought was novae. I’m really surprised that they didn’t make it onto the above list. I’m also surprised that flare stars, brown dwarfs and masers flare brightly enough in radio for that to be detected. Nice to know :-)
> there have only been a few blind radio surveys that have searched efficiently for radio transients.
I’m pleasantly surprised that there are any. It’s not an easy task. Hold on. SETI at Arecibo did a blind search for radio transients. But that’s for shorter duration transients.
> recent radio transient monitoring programs are revealing potentially new types of astronomical sources including:
The Lorimer burst, I was wondering if that was going to turn up.
> we have conducted a blind search for radio transients in the Galactic center (GC) at 235 and 330 MHz using archival VLA observations made between 1989 and the present, and monitoring observations with both the VLA and Giant Metrewave Radio Telescope (GMRT) beginning in 2002.
What’s the GMRT? It’s a giant radio telescope in India! Thirty fully steerable parabolic radio telescopes of 45 metre diameter. The kept that news quiet.
> Our motivation is that the naturally wide fields of view obtained at lower frequencies combined with the high stellar densities toward the GC provide an efficient means for searching for radio transients.
Yep.
> We detected three radio transients, for which no counterpart has been detected at high energies, and therefore would not have been detected in the more conventional manner of following-up newly discovered X-ray or γ-ray transients. These three radio transients have markedly different observed properties. … The source exhibited potentially multiple short bursts, of a duration no more than about 10 days, followed by a long burst beginning on 2007 December 17 and continuing until at least 2007 May 15 when our 2007 monitoring campaign ended. This last burst appears to have a fast rise, reaching the peak in about one month, and then decaying over the next four months.
Aliens?
PS, read that as 2006 December 17 rather than 2007.
> The closest source is Sgr E19, which is faintly visible about 2’ south of GCRT J1742–3001 in Figure 1. This source is described as a possible candidate young supernova remnant
> (We) have considered the possibility that the emission from GCRT J1742–3001 arises from radio activity in a foreground flaring star. In particular … the detection of radio flares having no apparent associated X-ray emission is not uncommon. For example, radio flares from UV Ceti stars with durations from seconds to minutes were detected at low frequencies … The radio flares from YZ CMi and Wolf 424 were found to have steep spectra (α ∼ −2.5) between 196 and 318 MHz.
Timescale. Radio flares from flare stars have the timesacale “seconds to minutes” and for the new variable source five months. So, unlikely to be a flare star. Despite the similar spectra.