A search for the optical counterpart to the magnetar CXOU J010043.1-721134

After our tentative detection of an optical counterpart to CXOU J010043.1-721134 from archival Hubble Space Telescope (HST) imaging, we have followed up with further images in four bands. Unfortunately, the source originally identified is not confirmed. We provide deep photometric limits in four bands and accurate photometry of field stars around the location of the magnetar.Comment: 9 pages, accepted by Ap

Possible Optical Detection of the Anomalous X-ray Pulsar CXOU J010043.1-721134

Archival Hubble Space Telescope Wide Field/Planetary Camera 2 observations of the Small Magellanic Cloud serendipitously reveal a possible counterpart to the Anomalous X-ray Pulsar CXOU J010043.1-721134. The candidate is faint, but its location and strange colours make it an interesting object. We estimate, that the probability of such a detection being due to a non-physical source is less than 1.5%. We have tried to confirm the identification with Gemini-South and Magellan, but the conditions were insufficiently favourable. If confirmed, the object will allow the first detailed studies of the optical and ultraviolet emission of magnetars.Comment: 9 pages LaTeX, 2 figures. Accepted for publication in ApJ

Kinematic and morphological modeling of the bipolar nebula Sa2-237

We present [OIII]500.7nm and Halpha+[NII] images and long-slit, high resolution echelle spectra in the same spectral regions of Sa2--237, a possible bipolar planetary nebula. The image shows a bipolar nebula of about 34" extent, with a narrow waist, and showing strong point symmetry about the central object, indicating it's likely binary nature. The long slit spectra were taken over the long axis of the nebula, and show a distinct ``eight'' shaped pattern in the velocity--space plot, and a maximum projected outflow velocity of V=106km/s, both typical of expanding bipolar planetary nebulae. By model fitting the shape and spectrum of the nebula simultaneously, we derive the inclination of the long axis to be 70 degrees, and the maximum space velocity of expansion to be 308 km/s. Due to asymmetries in the velocities we adopt a new value for the system's heliocentric radial velocity of -30km/s. We use the IRAS and 21cm radio fluxes, the energy distribution, and the projected size of Sa2-237 to estimate it's distance to be 2.1+-0.37kpc. At this distance Sa2-237 has a luminosity of 340 Lsun, a size of 0.37pc, and -- assuming constant expansion velocity -- a nebular age of 624 years. The above radial velocity and distance place Sa2--237 in the disk of the Galaxy at z=255pc, albeit with somewhat peculiar kinematics.Comment: 10pp, 4 fig

Trichomoniasis of turkeys

Cover title

Evidence for a Massive Neutron Star from a Radial-Velocity Study of the Companion to the Black Widow Pulsar PSR B1957+20

The most massive neutron stars constrain the behavior of ultra-dense matter, with larger masses possible only for increasingly stiff equations of state. Here, we present evidence that the black widow pulsar, PSR B1957+20, has a high mass. We took spectra of its strongly irradiated companion and found an observed radial-velocity amplitude of K_obs=324+/-3 km/s. Correcting this for the fact that, due to the irradiation, the center of light lies inward relative to the center of mass, we infer a true radial-velocity amplitude of K_2=353+/-4 km/s and a mass ratio q=M_PSR/M_2=69.2+/-0.8. Combined with the inclination i=65+/-2 deg inferred from models of the lightcurve, our best-fit pulsar mass is M_PSR=2.40+/-0.12 M_sun. We discuss possible systematic uncertainties, in particular in the lightcurve modeling. Taking an upper limit of i<85 deg based on the absence of radio eclipses at high frequency, combined with a conservative lower-limit to the motion of the center of mass, K_2>343 km/s (q>67.3), we infer a lower limit to the pulsar mass of M_PSR>1.66 M_sun.Comment: 7 pages, 3 figures, 1 table, accepted for publication in ApJ; revision includes more detail on the spectral classification and discussion of other recent high neutron-star masse

The magnetar emission in the IR band: the role of magnetospheric currents

There is a general consensus about the fact that the magnetar scenario provides a convincing explanation for several of the observed properties of the Anomalous X-ray Pulsars and the Soft Gamma Repeaters. However, the origin of the emission observed at low energies is still an open issue. We present a quantitative model for the emission in the optical/infrared band produced by curvature radiation from magnetospheric charges, and compare results with current magnetars observations.Comment: 6 Pages, 2 Figures. Astrophysics and Space Science, in press. Proceedings of the ICREA Workshop on The High-Energy Emission from Pulsars and their Systems, Sant Cugat, April 12-16 201

Physical Activity and Social Cognitive Theory Outcomes of an Internet-Enhanced Physical Activity Intervention for African American Female College Students

Background. African American women report low levels of physical activity (PA) and are disproportionately burdened by related chronic diseases. This pilot study tested a 6-month theory-based (Social Cognitive Theory, SCT) culturally-relevant website intervention to promote PA among African American female college students. Materials and Methods. A single group pre-post test design (n=34) was used. PA and associated SCT constructs (outcome expectations, enjoyment, self-regulation, social support) were assessed at baseline, 3 months and 6 months. Results. The sample was comprised of mostly obese (M BMI= 35.4, SD=6.82) young adults (M age= 21.21 years, SD=2.31). Fifty percent of the sample completed all assessments. Intent-to-treat analyses showed that participants reported a significant median improvement in moderate-to-vigorous physical activity from 82.5 minutes/week (M=81.76, SD=76.23) at baseline to 115.0 minutes/week (M=122.44,SD=97.93) at 3 months (Wilcoxon z=2.39, p=.02). However these gains appear to have attenuated by 6 months (Median= 82.5 minutes/week, M=96.73, SD=84.20; Wilcoxon z=1.02, p=.31). Significant increases from baseline to 6 months were found in self-regulation for PA (p=.02) and social support for PA from friends (p=.02). Changes in the SCT variables were not significantly associated with changes in PA; however, this may have been due to small sample size. Conclusions. Future studies with larger samples and more aggressive retention strategies (e.g., more frequent incentives, prompts for website use) are needed to further explore the applicability of culturally relevant web-based approaches to promote PA in this at-risk population

Correlated Infrared and X-ray Flux Changes Following the 2002 June Outburst of the Anomalous X-ray Pulsar 1E 2259+586

We present the results of a near-infrared monitoring program of the Anomalous X-ray Pulsar 1E 2259+586, performed at the Gemini Observatory. This program began three days after the pulsar's 2002 June outburst, and spans ~1.5 years. We find that after an initial increase associated with the outburst, the near-infrared flux decreased continually and reached the pre-burst quiescent level after about one year. We compare both the near-infrared flux enhancement and its decay to those of the X-ray afterglow, and find them to be remarkably consistent. Fitting simple power laws to the RXTE pulsed flux and near-infrared data for t>1 day post-burst, we find the following decay indices: alpha=-0.21+/-0.01 (X-ray), alpha=-0.21+/-0.02 (near-infrared), where flux is a function of time such that F is proportional to t^alpha. This suggests that the enhanced infrared and X-ray fluxes have a physical link post-outburst, most likely from the neutron-star magnetosphere.Comment: 11 pages, 1 figure, accepted for publication in ApJL; minor wording changes, added observation program IDs, improved figure resolutio

The variable radio-to-X-ray spectrum of the magnetar XTE J1810-197

We have observed the 5.54s anomalous X-ray pulsar XTE J1810-197 at radio, millimeter, and infrared (IR) wavelengths, with the aim of learning about its broad-band spectrum. At the IRAM 30m telescope, we have detected the magnetar at 88 and 144GHz, the highest radio-frequency emission ever seen from a pulsar. At 88GHz we detected numerous individual pulses, with typical widths ~2ms and peak flux densities up to 45Jy. Together with nearly contemporaneous observations with the Parkes, Nancay, and Green Bank telescopes, we find that in late 2006 July the spectral index of the pulsar was -0.5<alpha<0 over the range 1.4-144GHz. Nine dual-frequency Very Large Array and Australia Telescope Compact Array observations in 2006 May-September are consistent with this finding, while showing variability of alpha with time. We infer from the IRAM observations that XTE J1810-197 remains highly linearly polarized at millimeter wavelengths. Also, toward this pulsar, the transition frequency between strong and weak scattering in the interstellar medium may be near 50GHz. At Gemini, we detected the pulsar at 2.2um in 2006 September, at the faintest level yet observed, K_s=21.89+-0.15. We have also analyzed four archival IR Very Large Telescope observations (two unpublished), finding that the brightness fluctuated within a factor of 2-3 over a span of 3 years, unlike the monotonic decay of the X-ray flux. Thus, there is no correlation between IR and X-ray flux, and it remains uncertain whether there is any correlation between IR and radio flux.Comment: Accepted for publication in ApJ; contains improved discussion of infrared uncertaintie