Bright Galaxies

Summary

A search for bright galaxies that were missed by prior SDSS spectroscopic surveys

Finding Targets

An object whose ANCILLARY_TARGET1 value include one or more of the bitmasks in the following table was targeted for spectroscopy as part of this ancillary target program. See SDSS-III bitmasks to learn how to use these values to identify objects in this ancillary target program.

Program (bit name)	Bit Number
BRIGHTGAL	21

Description

Bright galaxies were commonly missed in the original SDSS spectroscopic survey due to fiber collisions, bright limits (objects with model magnitudes r >15, g >15, or i >14.5 were excluded), and errors in the deblending of overlapping images (Strauss et al. 2002). Approximately 10% of the brightest galaxies were not spectroscopically observed (Fukugita et al. 2007). To improve the completeness of this spectroscopic sample, we have implemented the selection criteria described below.

Target Selection Details

Objects were chosen with

Petrosian radius >1" in r (to reject stars)
No saturated pixels
Extinction-corrected, Petrosian (Petrosian 1976; Strauss et al. 2002) r magnitude between 10 and 16.
Extinction-corrected Petrosian magnitude i <20 and z <20 (to exclude misidentified satellite tracks which would not show up in the other bands).

Galaxies without spectra (24,000 from the original list of 93,000) where then visually vetted to remove foreground stars that remained in the sample, detector artifacts (e.g. internal reflections) that were misidentified, and other sources of confusion. In cases where a foreground star was misidentified as the galaxy center, the target position was moved to the correct position. In cases of merging galaxies, we visually identified multiple targets corresponding to the centers of each galaxy. The list was cross-correlated with the Third Reference Catalog of Bright Galaxies (RC3 de Vaucouleurs et al. 1991; Corwin et al. 1994), and any targets that did not appear in the original SDSS spectroscopic survey were added to the target list (0.05% of the final list). Finally, targets within 2'' of a star that appears in the Tycho-2 Catalog (Høg et al. 2000) were removed. The final sample includes 8637 galaxies over the BOSS footprint.

Primary contact

Demitri Muna
New York University
demitri.muna -at- nyu.edu

REFERENCES

Fukugita, M., Nakamura, O., Okamura, S., Yasuda, N., Barentine, J.C., Brinkmann, J., Gunn, J.E., Harvanek, M., Ichikawa, T., Lupton, R.H., Schneider, D.P., Strauss, M.A., & York, D.G., 2007, AJ, 134, 579 doi:10.1086/518962
Strauss, M. A., Weinberg, D.H., Lupton, R.H., Narayanan, V.K., Annis, J., Bernardi, M., Blanton, M., Burles, S., Connolly, A.J., Dalcanton, J., Doi, M., Eisenstein, D., Frieman, J.A., Fukugita, M., Gunn, J.E., Ivezić, Ž, Kent, S., Kim, R.S.J., Knapp, G.K., Kron, R.G., Munn, J.A., Newberg, H.J., Nichol, R.C., Okamura, S., Quinn, T.R., Richmond, M.W., Schlegel, D.J., Shimasaku, K., SubbaRao, M., Szalay, A.S., Vanden Berk, D., Vogeley, M.S., Yanny, B., Yasuda, N., York, D.G., & Zehavi, I., 2002, AJ, 124, 1810 doi:10.1086/342343
Petrosian, V., 1976, ApJ, 209, L1 doi:10.1086/182253
Høg, E., Fabricius, C., Makarov, V.V., Urban, S., Corbin, T., Wycoff, G., Bastian, U., Schwekendiek, P., Wicenec, A., 2000, A&A, 355, L27, Link to PDF