2020/05/13 by Nathan J. Secrest, Nathan Secrest, Shobita Satyapal · 22 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Dwarf galaxy #Dwarf galaxy problem #Dwarf spheroidal galaxy #Elliptical galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminous infrared galaxy #Photometry (optics) #Stellar mass #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · open access · doi:10.3847/1538-4357/ab9309
published in The Astrophysical Journal 900(1), 56 (IOP Publishing) · 12 pages, 3 figures, accepted to ApJ
arxiv created 2020/05/13 · openalex created_date 2020/05/21 · openalex publication_date 2020/08/31 · arxiv updated 2020/09/09 · openalex updated_date 2026/08/05
Abstract Using 8.4 yr of photometry from the AllWISE/NEOWISE multi-epoch catalogs, we compare the mid-infrared variability properties of a sample of 2197 dwarf galaxies ( M ⋆ < 2 × 10 9 h −2 M ☉ ) to a sample of 6591 more massive galaxies ( M ⋆ ≥ 10 10 h −2 M ☉ ) matched in mid-infrared apparent magnitude. We find only two dwarf galaxies with mid-infrared variability, a factor of ∼10 less frequent than the more massive galaxies ( p = 6 × 10 −6 ), consistent with previous findings of optical variability in low-mass and dwarf galaxies using data with a similar baseline and cadence. Within the more massive control galaxy population, we see no evidence for a stellar mass dependence of mid-infrared variability, suggesting that this apparent reduction in the frequency of variable objects occurs below a stellar mass of ∼10 10 h −2 M ☉ . Compared to the more massive galaxies, active galactic nuclei (AGNs) selected in dwarf galaxies using either their mid-infrared color or optical emission-line classification are systematically missed by variability selection. Our results suggest, in agreement with previous optical studies at similar cadence, that variability selection of AGNs in dwarf galaxies is ineffective unless higher-cadence data are used.