Stars in the USNO-B1 Catalog with Proper Motions Between 1.0 and 5.0 arcseconds per year

This paper examines a subset of objects from the USNO-B1 catalogue with listed proper motions between 1.0 and 5.0 arcseconds per year. We look at the degree of contamination within this range of proper motions, and point out the major sources of spurious high proper motion objects. Roughly 0.1% of the objects in the USNO-B1 catalogue with listed motions between 1.0 and 5.0 arcseconds per year are real. Comparison with the revised version of Luyten's Half Second catalogue indicates that USNO-B1 is only about 47% complete for stars in this range. Preliminary studies indicate that there may be a dip in completeness in USNO-B1 for objects with motions near 0.1 arcseconds per year. We also present two new stars with motions between 1.0 and 5.0 arcseconds per year, 36 new stars with confirmed motions between 0.1 and 1.0 arcseconds per year, several new common proper motion pairs, and the recovery of LHS237a (VBs3).Comment: 42 pages, 16 figures, uses AASTeX v5.2, accepted by A

Detection of [OI] 6300 and Other Diagnostic Emission Lines in the Diffuse Ionized Gas of M33 with Gemini-North

We present spectroscopic observations of diffuse ionized gas (DIG) in M33 near the HII region NGC 604. We present the first detection of [OI] 6300 in the DIG of M33, one of the critical lines for distinguishing photo- from shock ionization models. We measure [OI]/Ha in the range of 0.04 to 0.10 and an increase in this ratio with decreasing emission measure. Our measurements of [SII]/Ha and [NII]/Ha also rise with decreasing emission measure, while our [OIII]/Hb measurements remain fairly constant. We have one tentative detection of He I in the region of brightest emission measure, with a ratio of He I/Ha = 0.033 +- 0.019, indicating that the helium is at least partially ionized. We compare our observed emission line ratios to photoionization models and find that field star ionization models do not fit our data well. Leaky HII region models are consistent with our data, without the need to invoke additional ionization mechanisms to fit our [OI] or [OIII] measurements. The closest large HII region is NGC 604 and is therefore a likely candidate for the source of the ionizing photons for the gas in this region.Comment: 12 pages, 4 figures, accepted by ApJ

On the Evidence for Axion-like Particles from Active Galactic Nuclei

Burrage, Davis, and Shaw recently suggested exploiting the correlations between high and low energy luminosities of astrophysical objects to probe possible mixing between photons and axion-like particles (ALP) in magnetic field regions. They also presented evidence for the existence of ALP's by analyzing the optical/UV and X-ray monochromatic luminosities of AGNs. We extend their work by using the monochromatic luminosities of 320 unobscured Active Galactic Nuclei from the Sloan Digital Sky Survey/Xmm-Newton Quasar Survey (Young et al., 2009), which allows the exploration of 18 different combinations of optical/UV and X-ray monochromatic luminosities. However, we do not find compelling evidence for the existence of ALPs. Moreover, it appears that the signal reported by Burrage et al. is more likely due to X-ray absorption rather than to photon-ALP oscillation.Comment: 16 pages, 12 figures. Updated to reflect the minor changes introduced in the published versio

Identification of four RXTE Slew Survey sources with nearby luminous active galactic nuclei

Based on RXTE scans and observations with the SWIFT/XRT telescope and INTEGRAL observatory, we report the identification of four X-ray sources discovered during the RXTE Slew Survey of the |b|>10deg sky with nearby (z ~ 0.017-0.098) luminous (log L_2-10keV ~ 42.7-44 erg/s) active galactic nuclei. Two of the objects exhibit heavily intrinsically absorbed X-ray spectra (NHL~10^23 cm^-2).Comment: 4 pages, 2 figures. Sibmitted to Astronomy and Astrophysics Letter

RMS Radio Source Contributions to the Microwave Sky

Cross-correlations of the WMAP full sky K, Ka, Q, V, and W band maps with the 1.4 GHz NVSS source count map and the HEAO I A2 2-10 keV full sky X-ray flux map are used to constrain rms fluctuations due to unresolved microwave sources in the WMAP frequency range. In the Q band (40.7 GHz), a lower limit, taking account of only those fluctuations correlated with the 1.4 GHz radio source counts and X-ray flux, corresponds to an rms Rayleigh-Jeans temperature of ~ 2 microKelvin for a solid angle of one square degree. The correlated fluctuations at the other bands are consistent with a beta = -2.1 +- 0.4 frequency spectrum. Using the rms fluctuations of the X-ray flux and radio source counts, and the cross-correlation of these two quantities as a guide, the above lower limit leads to a plausible estimate of ~ 5 microKelvin for Q-band rms fluctuations in one square degree. This value is similar to that implied by the excess, small angular scale fluctuations observed in the Q band by WMAP, and is consistent with estimates made by extrapolating low-frquency source counts.Comment: 17 pages, 8 figures, submitted to Ap

Source Matching in the SDSS and RASS: Which Galaxies are Really X-ray Sources?

The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may be weak, or obscured by dust. To aid in the understanding of weakly accreting black holes in the local universe, a large sample of galaxies with X-ray detections is needed. We cross-match the ROSAT All Sky Survey (RASS) with galaxies from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to create such a sample. Because of the high SDSS source density and large RASS positional errors, the cross-matched catalog is highly contaminated by random associations. We investigate the overlap of these surveys and provide a statistical test of the validity of RASS-SDSS galaxy cross-matches. SDSS quasars provide a test of our cross-match validation scheme, as they have a very high fraction of true RASS matches. We find that the number of true matches between the SDSS main galaxy sample and the RASS is highly dependent on the optical spectral classification of the galaxy; essentially no star-forming galaxies are detected, while more than 0.6% of narrow-line Seyferts are detected in the RASS. Also, galaxies with ambiguous optical classification have a surprisingly high RASS detection fraction. This allows us to further constrain the SEDs of low-luminosity active galaxies. Our technique is quite general, and can be applied to any cross-matching between surveys with well-understood positional errors.Comment: 10 pages, 10 figures, submitted to The Astronomical Journal on 19 June 200

Perceptions of an Aviation Flight Practicum: A Follow-Up Study of Graduates of an Aviation Flight Practicum Course

The purpose of this paper is to present the results of a follow-up survey of graduates of a collegiate aviation flight training program who completed an advanced flight practicum course prior to graduating. The AF 304--Practicum in Air Carrier Operations course at Southern Illinois University Carbondale is designed to provide advanced training and additional multi-engine flight time for flight students while providing transportation services for university personnel. Graduates of the course were asked to complete a survey regarding their experiences in AF 304. Specifically, they were asked their current employment situation, what effect(s) AF 304 had on their piloting skills and career, and what benefits they gained as a result of taking the course. Of 77 respondents, 65 indicated that they were employed as pilots at the time. Overall, the respondents agree that the course improved their flying and aeronautical decision making skills, and several noted an increase in their confidence. Additionally, they indicate having derived a variety of other benefits from the course, including more experience in various weather conditions, passenger carrying experience, a greater awareness of operations in the Air Traffic Control system, and better knowledge of advanced systems and avionics

XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources

The 18806 ROSAT All Sky Survey Bright Source Catalog (RASS/BSC) X-ray sources are quantitatively cross-associated with near-infrared (NIR) sources from the Two Micron All Sky Survey Point Source Catalog (2MASS/PSC). An association catalog is presented, listing the most likely counterpart for each RASS/BSC source, the probability Pid that the NIR source and X-ray source are uniquely associated, and the probability Pnoid that none of the 2MASS/PSC sources are associated with the X-ray source. The catalog includes 3853 high quality (Pid>0.98) X-ray--NIR matches, 2280 medium quality (0.98>Pid>0.9) matches, and 4153 low quality (0.9>Pid>0.5) matches. Of the high quality matches, 1418 are associations that are not listed in the SIMBAD database, and for which no high quality match with a USNO-A2 optical source was presented for the RASS/BSC source in previous work. The present work offers a significant number of new associations with RASS/BSC objects that will require optical/NIR spectroscopy for classification. For example, of the 6133 Pid>0.9 2MASS/PSC counterparts presented in the association catalog, 2411 have no classification listed in the SIMBAD database. These 2MASS/PSC sources will likely include scientifically useful examples of known source classes of X-ray emitters (white dwarfs, coronally active stars, active galactic nuclei), but may also contain previously unknown source classes. It is determined that all coronally active stars in the RASS/BSC should have a counterpart in the 2MASS/PSC, and that the unique association of these RASS/BSC sources with their NIR counterparts thus is confusion limited.Comment: 14 pages, 13 figures, 5 table

Imaging X-ray, Optical, and Infrared Observations of the Transient Anomalous X-ray Pulsar XTE J1810-197

We report X-ray imaging, timing, and spectral studies of XTE J1810-197, a 5.54s pulsar discovered by Ibrahim et al. (2003) in recent RXTE observations. In a set of short exposures with the Chandra HRC camera we detect a strongly modulated signal (55+/-4% pulsed fraction) with the expected period located at (J2000) 18:09:51.08, -19:43:51.7, with a uncertainty radius of 0.6 arcsec (90% C.L.). Spectra obtained with XMM-Newton are well fitted by a two-component model that typically describes anomalous X-ray pulsars (AXPs), an absorbed blackbody plus power law with parameters kT = 0.67+/-0.01 keV, Gamma=3.7+/-0.2, N_H=(1.05+/-0.05)E22 cm^-2, and Fx(0.5-10 keV) = 3.98E-11 ergs/cm2/s. Alternatively, a 2T blackbody fit is just as acceptable. The location of CXOU J180951.1-194351 is consistent with a point source seen in archival Einstein, Rosat, & ASCA images, when its flux was nearly two orders-of-magnitude fainter, and from which no pulsations are found. The spectrum changed dramatically between the "quiescent" and "active" states, the former can be modeled as a softer blackbody. Using XMM timing data, we place an upper limit of 0.03 lt-s on any orbital motion in the period range 10m-8hr. Optical and infrared images obtained on the SMARTS 1.3m telescope at CTIO show no object in the Chandra error circle to limits V=22.5, I=21.3, J=18.9, & K=17.5. Together, these results argue that CXOU J180951.1-194351 is an isolated neutron star, one most similar to the transient AXP AX J1844.8-0256. Continuing study of XTE J1810-197 in various states of luminosity is important for understanding and possibly unifying a growing class of isolated, young neutron stars that are not powered by rotation.Comment: 12 pages, 7 figures, AAS LaTex, uses emulateapj5.sty. Updated to include additional archival data and a new HRC observation. To appear in The Astrophysical Journa