The steering committee for Green Bank Interferometer radio monitoring has adopted some initial policies for the new GBI-NASA effort. Here we summarize the essential policies and indicate how sources can be added to the monitoring program.
There are three categories of sources to be included in the GBI-NASA program. The highest priority is observations of both transient and persistent galactic X-ray and Gamma-ray sources. The other two categories of sources are active stellar binary systems and extra galactic sources: AGN, blazars, etc. Amongst the prime sources are GRS1915+105, GRO J1655-40, Cyg X-3, Cyg X-1, GRS1716-249, SS433, and LSI+61 303. The observing program for GBI-NASA is expected to typically include about 20 sources in addition to those used for calibration and data quality checking. Preference will be given to radio sources proposed for high energy X-ray and gamma-ray simultaneous observations.
The GBI-NASA steering committee has adopted the policy that all GBI data will be made publicly available via anonymous ftp (osiris@gb.nrao.edu and cd to /pub/dist/data) and internet Web page (http://www.gb.nrao.edu/ gbint/gbint.html).
Researchers using X-ray and gamma-ray instruments to study sources that exhibit, or could exhibit, radio emission, can propose to include new sources in the GBI program by sending a short request for observations (RFO) via E-mail to the following people:
Marco Tavani tavani@astro.columbia.edu Chair of steering Comm. Bob Hjellming rhjellmi@nrao.edu Executive Comm. Elizabeth Waltman ewaltman@rira.nrl.navy.mil Executive Comm. Frank Ghigo fghigo@nrao.edu Executive Comm.The proposer should be aware of the GBI capabilities:
i) simultaneous observations at 2.3 and 8.3 GHz frequencies;
ii) typical sensitivity of 15-20 mJy at 2.3 GHz;
iii) possibility of multiple pointings per day;
iv) routine observations above -41 degrees declination, possibly
down to -45 degrees under special circumstances.
The RFO should always include the following:
1. The name(s) and institution(s) of the proposer(s).
2. The names(s) and type(s) of radio source(s).
3. Sky position(s) of arcsec accuracy (equinox B1950)
together with uncertainty estimate(s).
4. A brief description of the multiwavelength program, its scientific
objectives, and duration of observation(s) with instrument(s)
different from GBI.
5. A brief statement about the known or expected radio properties of
the source(s). (Note the GBI limiting flux density at 2.3 GHz
of 15-20 mJy).
6. The proposed duration of the GBI monitoring (not to exceed 1 month
for this program; extensions of this limit need to be strongly
justified).
7. A justification for possible multiple GBI pointings per day.
Based upon the guidelines from the GBI-NASA steering committee,
the source may be scheduled as soon as practicable, possibly within
1-2 days, or in cases where it is not easy to do, the RFO may be
passed on to the GBI-NASA steering committee for a decision. Either
the executive committee (Bob Hjellming, Elizabeth Waltman, Frank Ghigo)
or the Chair of the Steering Committee (Marco Tavani) will reply to
the RFO with regard to the scheduling of the source(s).
The primary sources for the GBI-NASA program occupy the 1300-0100
(=hhmm) range of right ascensions, with competition being most heavy
for 1500-2300. Since the GBI is only a two-element interferometer
operating simultaneously at 2.2 and 8.3 GHz, sources with largely
unknown positions may need to be identified first at radio or optical
wavelengths before they can feasibly be observed by the GBI.
However, in the case of important new sources, positions good to
a few arcminutes or less may be proposed, and the extraction of
the radio source information can later be obtained from analysis of
archived data after a position good to under one arcsecond is
determined.
The initial GBI program to be used at GBI startup, which is
expected before the middle of November 1996, and before the GBI-NASA
RFO system is operating, includes the following sources.
Comments on whether these, or other proposed sources, are objects
of study in multi wavelength campaigns may determine whether
they remain on the program and the time invested in their observations.
GRO J1655-40 (XRN Sco 1994)
GRS 1716-249 (XRN Oph 1993, GRO J1719-24)
Sgr A* (1742-289)
SS433 (1909+048)
Aql X-1 (1908+005)
GRS 1915+105
Cyg X-1 (1956+351)
Cyg X-3 (2030+407)
LSI+61 303 (0236+610)
HR1099 (0334+004)
Algol (0304+408)
0336-019 (CTA26)
0430+289
0528+134
0716+714
0851+202 (OJ287)
0954+658
1253-055 (3C279)
Delta Lib (1458-073)
The GBI-NASA Steering Committee:
Robin Corbet corbet@rosserv.gsfc.nasa.gov
Frank Ghigo fghigo@nrao.edu
Eric Grove grove@osse.nrl.navy.mil
Alan Harmon harmon@SSLMOR.msfc.nasa.gov
Robert Hjellming rhjellmi@nrao.edu
Chris Shrader shrader@grossc.gsfc.nasa.gov,
Marco Tavani tavani@carmen.phys.columbia.edu (Chair)
Elizabeth Waltman ewaltman@rira.nrl.navy.mil