The Q band VLBI survey wiht KVN/VERA


Introduction

The popultion of compact sources at high frequncies is not stidied in full details. We will condact in 2012 an inteferometric survey at 43 GHz (Q-band) using the Korean VLBI Network (KVN) and the VLBI Exploration of Radio Astrometry (VERA) arrays, in total seven antennas.

Scientific goal

We propose to perform a Q-band imaging survey with the goal to get images of all compact continuum sources with δ > -20° with anticipated correlated flux densities greater than 350 mJy. The major scientific goal is to study the population of high frequency compact radio sources as a whole. In particular, we will

For all observed sources we will analyze not only new Q-band images, but also existing images at S, X, and K-bands. It is essential that the proposed survey will be complete at a a given correlated flux denisity, and therefore, the conclusions drawn from analysus of results can be generalized on the entire population. The results of this survey are supposed to remain the legacy VERA projects in the area of AGN study.

People

Team members (in alphabetic order):

Mareki Honma NAOJ, Japan
Yury Kovalev Astrospace Center, Russia
Sang-Sung Lee KASI, South Korea
Junghwan Oh KASI, South Korea
Leonid Petrov Astrogeo Center, USA

Source list

Observations

The survey will be made in two campaigns. In the first fringe-search campaign we will use three-station KVN network and observe at Q-band a pool of ~600 candidate sources in two scans each. This fringe-search campaign is scheduled to be observed in November/December 2011, and analysis if these observations will be completed in December 2011. Those sources that will have correlated flux density greater than 350 mJy will be scheduled for an imaging campaign at a 7-station network of VERA and KVN. Each source will be observed in 6 scans of 2 minutes each.

The list of candidates for the fringe-search campaign is formed from the list of sources with the K-band correlated flux density greater than 350 mJy. These sources were observed in the KQ survey, VERA FSS, VERA KCAL, VGaPS, and EGaPS. This cumulative list of K-band sources at δ > -30°r; has completeness better than 95% at 350 mJy level. Therefore, this list will be automatically complete at Q-band provided the spectra of sources are falling. According to Massaradi (2011) the fraction of sources with rising spectra in range 10–20 GHz is 8%. The list will exclude sources for which Q-band images are publicly available from the KQ survey and from the Boston University monitoring program.

At present, we do not know exactly how many sources will be detected in the fringe search campaign. In the case if all the sources will be detected, the requested time for observing 600 targets in 6 scans of 90 seconds each, including time for slewing and observations of calibrators, will be 192 hours. We should stress that this is the maximal estimate. Realistically, we expect 300–400 sources will be detected at the KVN, and the amount of needed time for completion of this survey will be more likely in the range of 100–120 hours.

In addition to VLBI observations, we will perform single-dish Q-band flux measurements of the final target list during winter 2011/2012 at one of KVN stations.

Current status

Preliminary results

Data

References

  1. Lanyi, et al., The Celestial Reference Frame at 24 and 43 GHz. I. Astrometry 2010, AJ, 139, 1695

  2. Massardi M., et al., The Australia Telescope 20 GHz (AT20G) Survey: analysis of the extragalactic source sample 2011, MNRAS, 412, 318

  3. Petrov L., et al. VERA 22 GHz fringe search survey, 2007, AJ, 133, 2487

  4. Petrov, L., Kovalev, Y.Y., Fomalont, E., Gordon, D., The sixth VLBA Calibrator Survey — VCS6, 2008, AJ, 136, 580

  5. Petrov L., et al., he Very Long Baseline Array Galactic Plane Survey\u2014VGaPS 2011, AJ, 142, 5

  6. Petrov L., The EVN Galactic Plane Survey — EGaPS, 2012, MNRAS, 419, 1097

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This web page was prepared by Leonid Petrov ()
Last update: 2012.08.13_09:07:42