The Calibration of the WISE W1 and W2 Tully-Fisher Relation

In order to explore local large-scale structures and velocity fields, accurate galaxy distance measures are needed. We now extend the well-tested recipe for calibrating the correlation between galaxy rotation rates and luminosities -- capable of providing such distance measures -- to the all-sky, space-based imaging data from the Wide-field Infrared Survey Explorer (WISE) W1 ($3.4mu$m) and W2 ($4.6mu$m) filters. We find a linewidth to absolute magnitude correlation (known as the Tully-Fisher Relation, TFR) of $mathcal{M}^{b,i,k,a}_{W1} = -20.35 - 9.56 (log W^i_{mx} - 2.5)$ (0.54 magnitudes rms) and $mathcal{M}^{b,i,k,a}_{W2} = -19.76 - 9.74 (log W^i_{mx} - 2.5)$ (0.56 magnitudes rms) from 310 galaxies in 13 clusters. We update the I-band TFR using a sample 9% larger than in Tully & Courtois (2012). We derive $mathcal{M}^{b,i,k}_I = -21.34 - 8.95 (log W^i_{mx} - 2.5)$ (0.46 magnitudes rms). The WISE TFRs show evidence of curvature. Quadratic fits give $mathcal{M}^{b,i,k,a}_{W1} = -20.48 - 8.36 (log W^i_{mx} - 2.5) + 3.60 (log W^i_{mx} - 2.5)^2$ (0.52 magnitudes rms) and $mathcal{M}^{b,i,k,a}_{W2} = -19.91 - 8.40 (log W^i_{mx} - 2.5) + 4.32 (log W^i_{mx} - 2.5)^2$ (0.55 magnitudes rms). We apply an I-band -- WISE color correction to lower the scatter and derive $mathcal{M}_{C_{W1}} = -20.22 - 9.12 (log W^i_{mx} - 2.5)$ and $mathcal{M}_{C_{W2}} = -19.63 - 9.11 (log W^i_{mx} - 2.5)$ (both 0.46 magnitudes rms). Using our three independent TFRs (W1 curved, W2 curved and I-band), we calibrate the UNION2 supernova Type Ia sample distance scale and derive $H_0 = 74.4 pm 1.4$(stat) $pm 2.4$(sys) kms$^{-1}$ Mpc$^{-1}$ with 4% total error.

Giant Sparks at Cosmological Distances?

Millisecond duration bright radio pulses at 1.4-GHz with high dispersion measures (DM) were reported by Lorimer et al., Keane et al., and Thornton et al. Their all-sky rate is $approx 10^4$/day above $sim$1 Jy. Related events are Perytons -- similar pulsed, dispersed sources, but most certainly local. Suggested models of fast radio bursts (FRBs) can originate in the Earths atmosphere, in stellar coronae, in other galaxies, and even at cosmological distances. Using physically motivated assumptions combined with observed properties, we explore these models. In our analysis, we focus on the Lorimer event: a 30 Jy, 5-ms duration burst with DM$=$ 375 cm$^{-3}$ pc, exhibiting a steep frequency-dependent pulse width (the {it Sparker}). To be complete, we drop the assumption that high DMs are produced by plasma propagation and assume that the source produces pulses with frequency-dependent arrival time (chirped signals). Within this framework we explore a scenario in which Perytons, the {it Sparker}, and the FRBs are all atmospheric phenomenon occurring at different heights. This model is {it ad hoc} in that we cannot explain why Perytons at higher altitudes show greater DMs or exhibit narrower pulses. Nonetheless, we argue the {it Sparker} may be a Peryton. We end with two remarks. First, the detection of a single FRB by an interferometer with a kilometer (or longer) baseline will prove that FRBs are of extra-terrestrial origin. Second, we urge astronomers to pursue observations and understanding of Perytons since they form (at least) a formidable foreground for the FRBs.