Rising NIR and millimeter emission from VHE and Gamma-ray source PKS 0447-439

ATel #3819; Roberto Nesci (Uni. La Sapienza, Roma), Philip Edwards (CSIRO Astronomy and Space Science), Jamie Stevens (CSIRO Astronomy and Space Science), Roopesh Ojha (NASA/GSFC), Michael Dutka (Catholic U.), Faith Hungwe (Rhodes U., HartRAO), Tapio Pursimo (NOT, La Palma), Gino Tosti (Uni. Perugia), Matthias Kadler (Uni. Wuerzburg)
on 21 Dec 2011; 22:03 UT
Credential Certification: Roberto Nesci (roberto.nesci@uniroma1.it)

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We report rising NIR and millimeter emission from the source PKS 0447-439 which is being monitored by the TANAMI program (http://pulsar.sternwarte.uni-erlangen.de/tanami/; Ojha et al. 2010, A&A, 519, 45). This increase may be an indication of enhanced emission at high and very high energies. PKS 0447-439 (RA: 04h49m24.88s DEC: -43d50'09.7s, J2000; Healey et al. 2007 ApJS, 171, 61) is a gamma-ray source detected by the Fermi Large Area Telescope (1FGL J0449.5-4350; Abdo et al. 2010, ApJS, 188, 405). It was also detected at very high energies (E>100GeV) by H.E.S.S. (ATel#2350; Zech et al. 2011, arXiv:1105.0840). Its redshift has been variously reported as 0.107 (Craig & Fruscione 1997, AJ, 114, 4), ~ 0.2 (Perlman et al. 1998, ApJ, 115, 1253), 0.176 (lower limit; Landt & Bignall 2008, MNRAS, 391, 967), and 0.20 (Prandini et al. 2011, arXiv1110.4038). We began monitoring the source with REM (http://www.rem.inaf.it) in JHK bands in Sep. 2011 (MJD 55811), initially finding it at J=12.82+-0.04, brighter than its 2MASS value (J=13.89, Oct. 1999). A few years before (Dec. 1995) it was observed at J=14.26 in the DENIS survey. In the subsequent 8 pointings after our first observation the source increased its luminosity monotonically reaching J=12.28 +-0.01 on MJD 55913 (Dec. 18 2011). Our aperture photometry has 2 arcsec radius and is tied to a reference photometric sequence of 7 nearby stars selected from the 2MASS catalog. We are also observing this source with the Australia Telescope Compact Array (ATCA; http://www.narrabri.atnf.csiro.au/ ) every few weeks since May 2011 with "snapshot" observations at frequencies between 5.5 and 40 GHz, where each frequency is the centre of a 2 GHz wide band and the fluxes are calibrated against the ATCA primary flux calibrator PKS 1934-638. At frequencies from 5.5 through 19GHz there is no significant change in flux. However at 38 and 40 GHz (7.9 and 7.5mm) its flux has increased from 0.10 Jy on 2011Sep13 to 0.14 Jy on 2011Nov08 (where each flux density has a one-sigma uncertainty of +- 0.01 Jy at both epochs). We encourage multiwavelength observations particularly at high and very high energies. Further monitoring will be continued with the ATCA and REM telescopes and possible future activity will be reported using this platform.