We present first results of a campaign to find and identify new compact objects in the Galactic center. Selecting candidates from a combination of Chandra and 2MASS survey data, we search for ...accretion disk signatures via infrared spectroscopy. We have found the infrared counterpart to the Chandra source CXO J174536.1-285638, the spectrum of which has strong Brg and He I emission. The presence of C III, N III, and He II indicate a binary system. We suspect that the system is some form of high-mass binary system, either a high-mass X-ray binary or a colliding-wind binary.
ABSTRACT
This paper provides a catalogue of stars, quasars, and galaxies for the Southern Photometric Local Universe Survey Data Release 2 (S-PLUS DR2) in the Stripe 82 region. We show that a 12-band ...filter system (5 Sloan-like and 7 narrow bands) allows better performance for object classification than the usual analysis based solely on broad bands (regardless of infrared information). Moreover, we show that our classification is robust against missing values. Using spectroscopically confirmed sources retrieved from the Sloan Digital Sky Survey DR16 and DR14Q, we train a random forest classifier with the 12 S-PLUS magnitudes + 4 morphological features. A second random forest classifier is trained with the addition of the W1 (3.4 $\mu\mathrm{m} $) and W2 (4.6 $\mu\mathrm{m} $) magnitudes from the Wide-field Infrared Survey Explorer (WISE). Forty-four per cent of our catalogue have WISE counterparts and are provided with classification from both models. We achieve 95.76 per cent (52.47 per cent) of quasar purity, 95.88 per cent (92.24 per cent) of quasar completeness, 99.44 per cent (98.17 per cent) of star purity, 98.22 per cent (78.56 per cent) of star completeness, 98.04 per cent (81.39 per cent) of galaxy purity, and 98.8 per cent (85.37 per cent) of galaxy completeness for the first (second) classifier, for which the metrics were calculated on objects with (without) WISE counterpart. A total of 2926 787 objects that are not in our spectroscopic sample were labelled, obtaining 335 956 quasars, 1347 340 stars, and 1243 391 galaxies. From those, 7.4 per cent, 76.0 per cent, and 58.4 per cent were classified with probabilities above 80 per cent. The catalogue with classification and probabilities for Stripe 82 S-PLUS DR2 is available for download.
Opioids are commonly used for pain relief clinically and reduce hyperalgesia in most animal models. Two injections of acidic saline into one gastrocnemius muscle 5 days apart produce a long-lasting ...bilateral hyperalgesia without associated tissue damage. The current study was undertaken to assess the effects of opioid agonists on mechanical hyperalgesia induced by repeated intramuscular injections of acid. Morphine (mu-agonist), D-Ala(2),N-Me-Phe(4),Gly-ol(5)-enkephalin (mu-agonist; DAMGO), 4-((alpha)R)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl-N,N-diethylbenzamide (delta-agonist; SNC80), or (1S-trans)-3,4-dichloro-N-methyl-N-2-(1-pyrrolidinyl)cylcohexyl-benzeneacetamide hydrochloride (kappa-agonist; U50,488) were administered intrathecally to activate opioid receptors once hyperalgesia was developed. Mechanical hyperalgesia was assessed by measuring the withdrawal thresholds to mechanical stimuli (von Frey filaments) before the first and second intramuscular injection, 24 h after the second intramuscular injection, and for 1 h after administration of the opioid agonist or vehicle. Morphine, DAMGO, and SNC80 dose dependently increased the mechanical withdrawal threshold back toward baseline responses. The reduction in hyperalgesia produced by morphine and DAMGO was prevented by H-D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2) (CTAP) and that of SNC80 was prevented by naltrindole. U50,488 had no effect on the decreased mechanical withdrawal thresholds. Thus, activation of mu- and delta-, but not kappa-, opioid receptors in the spinal cord reduces mechanical hyperalgesia following repeated intramuscular injection of acid, thus validating the use of this new model of chronic muscle pain.
In this first of a two-paper sequence, we report techniques and results of the Cornell High-Order Adaptive Optics Survey (CHAOS) for brown dwarf companions. At the time of this writing, this study ...represents the most sensitive published population survey of brown dwarf companions to main-sequence stars for separations akin to our own outer solar system. The survey, conducted using the Palomar 200 inch (5 m) Hale Telescope, consists of Ks coronagraphic observations of 80 main-sequence stars out to 22 pc. At 1'' separation from a typical target system, the survey achieves median sensitivities 10 mag fainter than the parent star. In terms of companion mass, the survey achieves typical sensitivities of 25MJ (1 Gyr), 50MJ (solar age), and 60MJ (10 Gyr), using the evolutionary models of Baraffe and coworkers. Using common proper motion to distinguish companions from field stars, we find that no systems show positive evidence of a substellar companion (searchable separation ~1''-15''; projected separation ~10-155 AU at the median target distance). In the second paper of the series we will present our Monte Carlo population simulations.
In this second of a two-paper sequence, we present Monte Carlo population simulation results of brown dwarf companion data collected during the Cornell High-Order Adaptive Optics Survey (CHAOS) for ...brown dwarf companions. Making reasonable assumptions of orbital parameters (random inclination, random eccentricity, and random longitude of pericenter) and age distributions and using published mass functions, we find that the brown dwarf companion fraction around main-sequence stars is 0.0%-9.3% for the 25-100 AU semimajor axis region. We find a corresponding L dwarf companion fraction of 0.0%-3.3%. We compare our population analysis methods and results with techniques and results presented by several other groups. In this comparison we discover that systematic errors (most notably resulting from orbital projection effects) occur in the majority of previously published brown dwarf companion population estimates, leading authors to claim results not supported by the observational data.
We present a time-lapse sequence of 20 near-infrared (J and K' band) snapshots of the central 20 x 20 of the Crab pulsar wind nebula, taken at subarcsecond resolution with the Hokupa`a/QUIRC adaptive ...optics camera on the Gemini North Telescope and sampled at intervals of 10 minutes and 24 hr. It is observed that the equatorial wisps and polar knots in the termination shock of the pulsar wind appear to fluctuate in brightness on kilosecond timescales. Maximum flux variations of c24% c4% and c14% c4% relative to the mean (in 1.2 ks) are measured for the wisps and knots, respectively, with the greatest statistical significance in the J band, where the nebula background is less prominent. The J and K' flux densities imply different near-infrared spectra for the nonthermal continuum emission from the wisps and the outermost polar knot (the "sprite"), giving F sub(u) 8 u super(-0.56c0.12) and F sub(u)8u super(-0.21c0.13), respectively. The data are compared with existing optical and UV photometry and applied to constrain theories of the variability of the wisps (relativistic ion-cyclotron instability) and knots (relativistic fire-hose instability).
We use Wide-field InfraRed Camera (WIRC) infrared (IR) images of the Antennae (NGC 4038/4039) together with the extensive catalogue of 120 X-ray point sources to search for counterpart candidates. ...Using our proven frame-tie technique, we find 38 X-ray sources with IR counterparts, almost doubling the number of IR counterparts to X-ray sources that we first identified. In our photometric analysis, we consider the 35 IR counterparts that are confirmed star clusters. We show that the clusters with X-ray sources tend to be brighter, K
s≈ 16 mag, with (J−K
s) = 1.1 mag.
We then use archival Hubble Space Telescope (HST) images of the Antennae to search for optical counterparts to the X-ray point sources. We employ our previous IR-to-X-ray frame-tie as an intermediary to establish a precise optical-to-X-ray frame-tie with <0.6 arcsec rms positional uncertainty. Due to the high optical source density near the X-ray sources, we determine that we cannot reliably identify counterparts. Comparing the HST positions to the 35 identified IR star cluster counterparts, we find optical matches for 27 of these sources. Using Bruzual-Charlot spectral evolutionary models, we find that most clusters associated with an X-ray source are massive, and young, ∼ 106 yr.
We present deep near-infrared images of the Antennae galaxies, taken with the Palomar Wide-Field Infrared Camera (WIRC). The images cover a 4.'33 x 4.'33 (24.7 x 24.7 kpc) area around the galaxy ...interaction zone. We derive J- and K sub(s)-band photometric fluxes for 172 infrared star clusters and discuss details of the two galactic nuclei and the overlap region. We also discuss the properties of a subset of 27 sources that have been detected with WIRC, HST, and the VLA. The sources in common are young clusters of less than 10 Myr, which show no correlation between their infrared colors and 6 cm radio properties. These clusters cover a wide range in infrared color due to extinction and evolution. The average extinction is about A sub(V)6 2 mag, while the reddest clusters may be reddened by up to 10 mag.
We present evidence that similar to 30 minute episodes of jet formation in the Galactic microquasar GRS 1915+105 may sometimes entirely be a superposition of smaller, faster phenomena. We base this ...conclusion on simultaneous X-ray and infrared observations in 2002 July, using the Rossi X-Ray Timing Explorer and the Palomar 5 m telescope. On two nights, we observed quasi-periodic infrared flares from GRS 1915+105, each accompanied by a set of fast oscillations in the X-ray light curve (indicating an interaction between the jet and accretion disk). In contrast to similar observations in 1997, we find that the duration of each X-ray cycle matches the duration of its accompanying infrared flare, and we observed one instance in which an isolated X-ray oscillation occurred at the same time as a faint infrared "subflare" (of duration similar to 150 s) superimposed on one of the main flares. From these data, we are able to conclude that each X-ray oscillation had an associated faint infrared flare and that these flares blend together to form, and entirely comprise, the similar to 30 minute events we observed. Part of the infrared emission in 1997 also appears to be due to superimposed small flares, but it was overshadowed by infrared-bright ejections associated with the appearance of a sharp "trigger" spike in each X-ray cycle that were not present in 2002. We also study the evolution of the X-ray spectrum and find significant differences in the high-energy power-law component, which was strongly variable in 1997 but not in 2002. Taken together, these observations reveal the diversity of ways in which the accretion disk and jet in black hole systems are capable of interacting and solidify the importance of the trigger spike for large ejections to occur on similar to 30 minute timescales in GRS 1915+105.
Soft contact lenses are medical devices made from aqueous polymeric gels that are worn on the eye to correct refractive errors. These devices interrupt the natural contact pairing between the cornea ...and the eyelid and create two interfaces comprised of a synthetic material and the epithelia—contact lens surfaces versus (1) the cornea and (2) the eyelid conjunctiva. The cellular responses to friction and shear stress are thought to contribute to contact lens discomfort. This study performs direct contact shear experiments using in vitro biotribological experiments using a microtribometer equipped with a hydrogel membrane probe. Sections from commercial contact lenses are held in place on a spherically capped membrane probe during reciprocating sliding experiments against confluent monolayers of living human telomerase-immortalized corneal epithelial cells (hTCEpi). The contact lenses were loaded against the cell monolayers to physiological contact pressures between 400 and 1300 Pa under an applied load of 200 µN. The reciprocating distance was 3 mm, at a sliding speed of 1 mm/s, and the maximum duration of sliding was 1000 cycles. Five commercially available lenses (somofilcon A, stenfilcon A, etafilcon A, verofilcon A, and delefilcon A) were used to evaluate the cell layer responses to aqueous gels of differing composition, surface modulus, and lubricity. Cell damage was measured via propidium iodide staining and in situ fluorescence microscopy. The shear stresses varied from 16 ± 2 Pa (delefilcon A and verofilcon A) to 86 ± 12 Pa (stenfilcon A), and cell damage increased with increasing shear stress and increasing sliding duration. The two lens materials that have high water content surface gel layers (delefilcon A and verofilcon A) showed distinctly lower measures of cell damage as compared to the other lenses. Surface gel layers with a large polymer mesh size and high water content are shown to be an effective approach to lower the contact pressure, lower the friction coefficient, and thereby lower the shear stress and cell damage.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
