SPIRITS: Uncovering Unusual Infrared Transients with Spitzer

Journal Article · Thu Apr 20 00:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA6978· OSTI ID:22663692

Kasliwal, Mansi M.; Jencson, Jacob E.; Tinyanont, Samaporn; Cao, Yi; Cook, David ^[1]; Bally, John ^[2]; Masci, Frank; Armus, Lee ^[3]; Cody, Ann Marie ^[4]; Bond, Howard E. ^[5]; Contreras, Carlos ^[6]; Dykhoff, Devin A.; Amodeo, Samuel; Carlon, Robert L.; Cass, Alexander C.; Corgan, David T.; Faella, Joseph ^[7]; Boyer, Martha ^[8]; Cantiello, Matteo ^[9]; Fox, Ori D. ^[10] ; others, and

---

1. Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
2. Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States)
3. Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
4. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
5. Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
6. Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile)
7. Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S. E., University of Minnesota, Minneapolis, MN 55455 (United States)
8. NASA Goddard Space Flight Center, MC 665, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)
9. Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY 10010 (United States)
10. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between −11 and −14 (Vega-mag) and [3.6]–[4.5] colors between 0.3 mag and 1.6 mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1 mag yr{sup −1} to >7 mag yr{sup −1}. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.

• OSTI ID: 22663692
• Journal Information: Astrophysical Journal, Vol. 839, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COLOR
DECAY
EMISSION
GALAXIES
HYDROGEN
LUMINOSITY
MASS TRANSFER
NOVAE
STAR EVOLUTION
STELLAR WINDS
SUPERNOVAE