The Arecibo Zone of Avoidance Survey (ALFAZOA)

The Extragalactic ALFA Zone of Avoidance team is mapping the distribution of low-Galactic-latitude galaxies and large scale structures through detection of galaxies' 21-cm emission with ALFA. This Zone of Avoidance (ZOA) survey finds new HI galaxies which lie hidden behind the Milky Way, and also provides redshifts and other HI parameters for partially-obscured galaxies known at other wavelengths. In this way, we are illuminating the large scale structure in the local Universe in the low-Galactic-latitude sky where it is currently poorly mapped. The ZOA survey is one of the Extragalactic ALFA projects, and proceeds in tandem with Galactic ALFA and Pulsar ALFA projects. This "commensal" style of observing, using multiple backends simultaneously, increases enormously the scientific throughput of the telescope, making very efficient use of observing hours, particularly important during the popular Galactic time. The survey proceeds in two phases: shallow and deep.

Results from the Shallow Survey

The observations for the shallow survey (rms ~5mJy) are complete, and were conducted in commensal mode with Galactic ALFA projects, mapping about 1000 square degrees, 30° ≤ l ≤ 75°, |b| ≤ 10°. We have cataloged about 250 galaxies over half of the search area, including previously unrecognized nearby dwarfs (McIntyre et al. 2011). We are currently searching datacubes for the other half of the region, and expect to uncover a similar number of galaxies.

Sources from the ALFAZOA shallow survey

Figure: Upper panels: The inner Galaxy (left) and outer Galaxy (right) ZOA. The ALFAZOA shallow survey detections are shown in red. Small rectangular boxes show precursor regions. Previously known LEDA optical/IR galaxies with redshifts within 12,000 km/s are shown in blue. Parkes HIZOA galaxies are plotted in green. The lower panels indicate the Galactic extinction from the 100 µm DIRBE experiment (Schlegel et al. 1998) over the same regions of sky, with contours at AB = 1 mag (outer countour) and 3 mag (inner contour). We have cataloged galaxies over half of the search area behind the inner Galaxy, and thus expect to fill in the entire inner Galaxy ZOA accessible to Arecibo (dashed lines), within ± 10° of the plane, to 5 mJy. In the outer Galaxy ZOA, the detections are from our precursor observations (Henning et al. 2010) and the star marke the Crab nebula position. We will cover both sides of the Arecibo ZOA near the plane with the ongoing deep observations, to 1 mJy sensitivity

The ALFAZOA deep survey

We are surveying the ZOA in both the inner (30° ≤ l ≤ 75°) and outer (175° ≤ l ≤ 210°) Galaxy. The effective integration time for the deep survey is 5 minutes per beam, reaching 1 mJy rms. The higher sensitivity of this deep phase puts us on track to detect about 1500 galaxies over the ZOA, including low HI mass objects in the local universe, and HI galaxies at large distances. With the Mock spectrometers, we probe deep into redshift space (bandpass limit at ~40,000 km/s).

Detection from the ALFAZOA deep survey

Figure: HI spectrum showing a two-horned profile of one of our HI detections from the Deep survey, and the low noise (1 mJy) flat baselines we achieve.

ALFAZOA Data Release

* Publicly available data

Publications and Proceedings

* Discovery and Follow-up of a Nearby Galaxy from the Arecibo Zone of Avoidance Survey. McIntyre, T. P., Minchin, R. F., Henning, P. A., Kaur, A., &. Parton, B., 2011, ApJL, 739, 26.
ADS Bibcode: 2011ApJ...739L..26M.

* The Arecibo L-band Feed Array Zone of Avoidance Survey I: Precursor Observations through the Inner and Outer Galaxy. Henning, P. A., Springob, C. M., Minchin, R. F., Momjian, E., Catinella, B., McIntyre, T., Day, F., Muller, E., Koribalski, B., Rosenberg, J. L., Schneider, S., Staveley-Smith, L., van Driel, W., 2010, AJ, 139, 2130.
ADS Bibcode: 2010AJ....139.2130H.

* The Arecibo Zone of Avoidance Survey: First Results. McIntyre, T. P., Minchin, R., & Henning, P., 2012, AAS meeting 210, #410.03 (McIntyre Dissertation Abstract).
ADS Bibcode: 2012AAS...21941003M.

* The ALFA Zone of Avoidance Survey: Results from the Precursor Observations. Springob C. M., Henning, P. A., Catinella, B., Day, F., Minchin, R., Momjian, E., Koribalski, B., Masters, K. L., Muller, E., Pantoja, C., Putman, M., Rosenberg, J. L, Schneider, S., Staveley-Smith, L., 2008, IAU Symp. 244.
ADS Bibcode: 2008IAUS..244..383S
Download PDF of the poster

* Abstracts from AAS posters:
January 2012 (Truebenbach et al.)
May 2011 (McIntyre et al.)
January 2011 (McIntyre et al.)
January 2008 (Lamm et al.)
January 2007 (Springob et al.)
June 2006 (Henning et al.)

The ALFA ZOA Team

Catinella, Barbara MPA
Henning, Trish (PI) UNM
Koribalski, Baerbel ATNF
McIntyre, Travis UNM
Momjian, Emmanuel NRAO
Minchin, Robert NAIC
Putman, Mary Columbia U.
Rosenberg, Jessica GMU
Schneider, Stephen UMass
Springob, Christopher AAO
Staveley-Smith, Lister UWA
van Driel, Wim Paris Obs.
Viaz, Ensieh UWA

Useful links:

*Arecibo Astronomy pages
*E-ALFA pages
*Arecibo Legacy Fast ALFA (ALFALFA) survey project page
*Arecibo Ultra Deep Survey (AUDS) project page
*Arecibo Galaxy Environment Survey (AGES) project page
*Arecibo Observatory Telescope Schedule Database



Last updated: Friday, 31-Aug-2012 21:35:07 AST
E. Momjian