nature of the radio transient • Radio/optical spectral slopes • Optical/Infrared colors (slopes) It is going to be difficult to follow up ALL the transients • Optical identification can be useful to discriminate. Wednesday, June 13, 12
deg-2 days; 1000s time scales • Rate ~ 6.5 events deg-2 day-1 (18.6<B<23.8) Becker et al. 2004 • Three detections in B but Zero detections en R band (very blue) • M dwarf stars Kulkarni & Rau 2006 • 106 events per year 6000 in a 10 deg2 survey MPG/ESO survey 0.24 deg-2 days Rau et al. 2004 • Rate ~ 10-15 events deg-2 day-1 (3sigma <28; 16<R<23) • R band: 1 M dwarf; 2 CV/dwarf nova; Maybe one extragalactic Wednesday, June 13, 12
at Z=0.01-0.1 • Well defined time scales (weeks - years) . • Associated with host galaxies AGNs: • They can be strong radio sources (~Jy) • R~23 we should reach Z~2 ( Z=5 requires V~26) CVs (e.g. dwarf Novae) • Much brighter in the optical • Spectroscopy Wednesday, June 13, 12
• Well know X-rays/optical/IR/radio correlations GRBs • 2 per day (all sky) • Day-week time scales (mJy radio sources ) e.g. Chandra et al. 2007 • R=23.6 mean magnitude of host galaxies Ovaldsen et al. 2007 Active stars Usual suspects Wednesday, June 13, 12
• Well know X-rays/optical/IR/radio correlations GRBs • 2 per day (all sky) • Day-week time scales (mJy radio sources ) e.g. Chandra et al. 2007 • R=23.6 mean magnitude of host galaxies Ovaldsen et al. 2007 Active stars Güdel et al. 2002 Usual suspects Wednesday, June 13, 12
simpler the better • Quick identification of the nature of the transients: follow up? • Future population studies Radio (few GHz), optical (V/R bands) of a number of populations ★ Super Novae, GRBs ★ AGNs, X-ray binaries, different flavours of pulsars ★ Active stars ( Thanks to Manuel Güdel) CURRENT STATUS Wednesday, June 13, 12
We are investigating OPTICAL/RADIO ratios for several populations • Still some important caveats (biases, reddening...) • SOME IDEAS... • Optical colors • Infrared data Wednesday, June 13, 12