Absolute Calibration of the Auger Fluorescence Detectors

Absolute calibration of the Pierre Auger Observatory fluorescence detectors uses a light source at the telescope aperture. The technique accounts for the ombined effects of all detector components in a single measurement. The calibrated 2.5 m diameter light source fills the aperture, providing uniform illumination to each pixel. The known flux from the light source and the response of the acquisition system give the required calibration for each pixel. In the lab, light source uniformity is studied using CCD images and the intensity is measured relative to NIST-calibrated photodiodes. Overall uncertainties are presently 12%, and are dominated by systematics.Comment: 4 pages, 3 figure. Submitted to the 29th ICRC, Pune, Indi

The BL-Lac gamma-ray blazar PKS 0447-439 as a probable member of a group of galaxies at z=0.343

The BL-Lac blazar PKS 0447-439 is one of the brightest HE gamma-ray sources that were first detected by Fermi-LAT. It was also detected by H.E.S.S. at VHE gamma-rays, which allowed constraining the redshift of PKS 0447-439 by considering the attenuation caused by gamma-ray interactions with ambient photons in the extragalactic background light (EBL). This constraint agreed with color-magnitude and spectroscopic redshift constraints (0.179 < z < 0.56), Recently, however, a much higher redshift was proposed for this blazar (z > 1.2). This value was debated because if true, it would imply either that the relevant absorption processes of gamma-rays are not well understood or that the EBL is dramatically different from what is believed today. This high redshift was not confirmed by three independent new spectroscopic observations at high signal-to-noise ratios. Given that BL-Lac are typically hosted by elliptical galaxies, which in turn are associated with groups, we aim to find the host group of galaxies of PKS 0447-439. The ultimate goal is to estimate a redshift for this blazar. Spectra of twenty-one objects in the field of view of PKS 0447-439 were obtained with the Gemini Multi-Object Spectrograph. Based on the redshifts and coordinates of these galaxies, we searched for groups of galaxies. Using a deep catalog of groups, we studied the probability of finding by chance a group of galaxies in the line of sight of PKS 0447-439. We identified a group of galaxies that was not previously cataloged at z = 0.343 with seven members, a virial radius of 0.42 Mpc, and a velocity dispersion of 622 km s^-1. We found that the probability of the host galaxy of PKS 0447-439 to be a member of the new group is >= 97%. Therefore, we propose to adopt z = 0.343 +- 0.002 as the most likely redshift for PKS 0447-439.Comment: Accepted for publication in A&

La Llorona: A Glimpse into the Representation of Women in Myth and Media

The story of La Llorona has been passed down from generation to generation in different Hispanic communities, often used as a ghost story to keep children from misbehaving. There are many versions of her origin, but the main story is about a woman who is having issues with her husband, where he is either cheating on her or she is jealous of the attention he gives to their children. She then ends up drowning her children, either on accident or on purpose, and is left to haunt the woods in search of other children to replace the ones she lost. The story changes depending on who is telling it, but the woman can often be viewed as either lonely and mistreated or jealous and mentally unstable. Most stories tend to lean towards the latter, bringing forth the issue of the misrepresentation of, specifically, Latin women in popular media. This view of La Llorona perpetuates the misogynistic idea that women are quick to overreact and make rash decisions. Looking at the different ways that La Lorona is depicted and who is telling these stories can help show the underlying meaning and consequences of this popular horror story