Ultraluminous Extragalactic Chemistry

At a distance of 77 Mpc, the Ultralumious galaxy Arp 220 is the closest extragalactic equivalent to Galactic hot cores. The low resolution SMA survey showed a highly excited confusion limited spectrum. The new ALMA snapshot spectral scan opens the possibility of chemically resolve the two nuclei at unprecedented sensitivity. When completed, it will be the widest survey ever done towards an extragalactic object. The model of Band 6 and 7 data already shows the chemical similarities between the interacting nuclei which may provide clues on the similar heating sources. Vibrationally excited transitions may be tracing the deeply embedded dust obscured active nuclei and/or hot compact star burst. This vibrational emission is the brightest ever measured in an extragalactic object, and even so compared with Galactic hot cores. In fact, the eastern one is the brightest in such vibrational emission. Water mega-maser emission also points towards a very compact sources likely related to star forming clumps within both Arp 220 nuclei.

THE 2008 MULTIWAVELENGTH CAMPAIGN OF THE TeV RADIO-GALAXY M 87

M 87 is the first and brightest radio galaxy detected in the TeV regime. It is the closest extragalactic object showing variability and the only one that does not have its jet pointing toward the line of sight. The structure of the M 87 jet is spatially resolved in X-ray, optical and radio observations. Time correlation between the TeV flux and emission at other wavelengths provides a unique opportunity to localize the VHE emission process occurring in active galaxy nuclei. For 10 years, M87 has been monitored in the TeV band by imaging air Cherenkov telescopes (IACT) as well as in X-ray, optical and radio bands. In 2008, the three main IACTs, H.E.S.S./MAGIC/VERITAS, coordinated their observations in a joint campaign. In February, high TeV activities with rapid flares have been detected. Contemporaneously, M 87 was observed with high resolution instruments in the X-ray (Chandra) and Radio band (VLBA).

VLBI and Broad-Band Radio Spectra Study of the Strongly Variable Extragalactic Object 0524+034

Results of the first measurements of a VLBI structure of 0524+034 at 6 cm at the EVN+HartRAO in 1999 and recent broad-band spectra monitoring data are reported. We suppose that precession of the relativistic jet can be one of the possible mechanisms to account for the observed milliarcsecond structure and the strong long-term variations of the spectrum. The detected rapid changes may be interpreted as a propagation of a shock in the inhomogeneous jet plasma, but interstellar scintillations can not be ruled out on the basis of available data.

Variability characteristics of Blazar 0J 287

Blazar OJ 287 is one of the best observed extragalactic objects. It's historical light curve goes back to 1890′s. Based on the historical behaviour Sillanpää et al. (1988) showed that OJ 287 displays large periodic outbursts, with a period of 11.7 years. We have monitored OJ 287 intensively for two years, during the OJ-94 project. This project was created for monitoring OJ 287 during its predicted new outburst in 1994. In the data archive we have over 7000 observations on OJ 287, in the radio, infrared and optical bands. This data archive contains the best ever obtained light curves for any extragalactic object. The optical light curve shows continuous variability down to time scales of tens of minutes. The variability observed in OJ 287 can be broken down to (at least) four different categories:

Results from the Second EUVE Source Catalog

We present the results of the Second EUVE Source Catalog, including all detections from the EUVE all-sky survey, the EUVE deep survey, and sources detected during dedicated instrument pointings. Where available, we furnish identifications of these objects and statistics with regard to type of stellar or extragalactic object.

Evidence of Relativistic Beaming in BL Lac-Type Objects

Multifrequency observations of a variable extragalactic object, when all acquired within the inferred variability time scale of the source, can provide clues to the source's energy mechanisms. A guest observer program with the International Ultraviolet Explorer satellite has provided the focus for such measurements of a few BL Lac-type and related objects at frequencies in the radio, mm, IR, visual and UV. Earlier-epoch X-ray measurements are included in subsequent model fitting. This paper summarizes some of the observations in this program. Synchrotron self-Compton (SSC) models are then applied to the data, leading to the conclusions that the objects are relativistically beamed and that radio emission, at least below a frequency of ~20 GHz, is from a separate source region.

Mark III VLBI Observations of the Nucleus of M81 at 2.3 and 8.3 GHz

The normal spiral galaxy M81, which has some characteristics of a Seyfert (Peimbert, Torres-Peimbert, 1981), has a flat spectrum in the radio range (de Bruyn et al., 1976), variable on the time scale of days (Crane et al., 1976), and detectable radiation at infrared (Rieke, Lebofsky, 1978) and X-ray wavelengths (Elvis, van Speybroeck, 1981). At a distance of ∼3.3 Mpc, M81 is the nearest extragalactic object with a nucleus detectable with VLBI (Kellermann et al., 1976). We report here on simultaneous VLBI observations made with the Mark III system at 2.3 and 8.3 GHz. Observations on 14 and 16 March 1981 utilized the 100 m diameter telescope in Effelsberg, W. Germany (MPIR); the 43 m telescope at Green Bank, WV (NRAO); and the 40 m telescope near Big Pine, CA (OVRO).