118745183
WISE DETECTION OF THE GALACTIC LOW-MASS X-RAY BINARIES
We report on the results from our search for the Wide-field Infrared Survey Explorer (WISE) detection of the Galactic low-mass X-ray binaries (LMXBs). Among 187 binaries cataloged in Liu et al., we find 13 counterparts and 2 candidate counterparts. For the 13 counterparts, 2 (4U 0614+091 and GX 339–4) have already been confirmed by previous studies to have a jet and 1 (GRS 1915+105) to have a candidate circumbinary disk, from which the detected infrared emission arose. Having collected the broadband optical and near-infrared data in the literature and constructed flux density spectra for the other 10 binaries, we identify that 3 (A0620–00, XTE J1118+480, and GX 1+4) are candidate circumbinary disk systems, 4 (Cen X-4, 4U 1700+24, 3A 1954+319, and Cyg X-2) had thermal emission from their companion stars, and 3 (Sco X-1, Her X-1, and Swift J1753.5–0127) are peculiar systems with the origin of their infrared emission rather uncertain. We discuss the results and WISE counterparts' brightness distribution among the known LMXBs, and suggest that more than half of the LMXBs would have a jet, a circumbinary disk, or both.
119218814
Infrared Observations of the Millisecond Pulsar Binary J1023+0038: Evidence for the Short-term Nature of Its Interacting Phase in 2000-2001
We report our multi-band infrared (IR) imaging of the transitional millisecond pulsar system J1023+0038, a rare pulsar binary known to have an accretion disk in 2000-2001. The observations were carried out with ground-based and space telescopes from near-IR to far-IRwavelengths. We detected the source in near-IR JH bands and Spitzer 3.6 and 4.5 mu m mid-IR channels. Combined with the previously reported optical spectrum of the source, the IR emission is found to arise from the companion star, with no excess emission detected in the wavelength range. Because our near-IR fluxes are nearly equal to those obtained by the 2MASS all-sky survey in 2000 February, the result indicates that the binary did not contain the accretion disk at the time, whose existence would have raised the near-IR fluxes to twice larger values. Our observations have thus established the short-term nature of the interacting phase seen in 2000-2001: the accretion disk existed for at most 2.5 yr. The binary was not detected by the WISE all-sky survey carried out in 2010 at its 12 and 22 mu m bands and our Herschel far-IR imaging at 70 and 160 mu m. Depending on the assumed properties of the dust, the resulting flux upper limits provide a constraint of <3 x 10(22)-3 x 10(25) g on the mass of the dust grains that possibly exist as the remnants of the previously seen accretion disk.
119124657
NEAR-INFRARED IMAGING OF WHITE DWARFS WITH CANDIDATE DEBRIS DISKS
We have carried out JHKs imaging of 12 white dwarf debris disk candidates from the WIRED Sloan Digital Sky Survey Data Release 7 catalog, aiming to confirm or rule out disks among these sources. On the basis of positional identification and the flux density spectra, we find that seven white dwarfs have excess infrared emission, but mostly at Wide-field Infrared Survey Explorer W1 and W2 bands. Four are due to nearby red objects consistent with background galaxies or very low mass dwarfs, and one exhibits excess emission at JHKs consistent with an unresolved L0 companion at the correct distance. While our photometry is not inconsistent with all seven excesses arising from disks, the stellar properties are distinct from the known population of debris disk white dwarfs, making the possibility questionable. In order to further investigate the nature of these infrared sources, warm Spitzer imaging is needed, which may help resolve galaxies from the white dwarfs and provide more accurate flux measurements.
121654775
The possible effect of scalar meson on the symmetry energy curve in the viewpoint of the quark-meson-coupling model
We give the energy density functional of quark-meson-coupling model within the Hartree-Fock approximation and make comparison with relativistic-mean-field and Skyrme-Hartree-Fock models. We find that the discrepancy of these models is mainly from the isovector channel of the energy density functional, which is also the major cause of different descriptions of symmetry energy against density. In the viewpoint of quark-meson-coupling model, the scalar meson through Fock exchange makes a density dependent form of the isovector channel which can soften the symmetry energy curve.
15737210
CORONAL LINES AND DUST FORMATION IN SN 2005ip: NOT THE BRIGHTEST, BUT THE HOTTEST TYPE IIn SUPERNOVA
We present optical photometry and spectroscopy of SN 2005ip for the first 3 yr after discovery, showing an underlying Type II-L supernova (SN) interacting with a steady wind to yield an unusual Type IIn spectrum. For the first ~160 days, it had a fast linear decline from a modest peak absolute magnitude of about –17.4 (unfiltered), followed by a plateau at roughly –14.8 for more than 2 yr. Initially having a normal broad-lined spectrum superposed with sparse narrow lines from the photoionized circumstellar medium (CSM), it quickly developed signs of strong CSM interaction with a spectrum similar to that of SN 1988Z. As the underlying SN II-L faded, SN 2005ip exhibited a rich high-ionization spectrum with a dense forest of narrow coronal lines, unprecedented among SNe but reminiscent of some active galactic nuclei. The line-profile evolution of SN 2005ip confirms that dust formation caused its recently reported infrared excess, but these lines reveal that it is the first SN to show clear evidence for dust in both the fast SN ejecta and the slower postshock gas. SN 2005ip's complex spectrum confirms the origin of the strange blue continuum in SN 2006jc, which also had postshock dust formation. We suggest that SN 2005ip's late-time plateau and coronal spectrum result from rejuvenated CSM interaction between a sustained fast shock and a clumpy stellar wind, where X-rays escape through the optically thin interclump regions to heat the preshock CSM to coronal temperatures.
14783547
The Detection of a Light Echo from the Type Ia Supernova 2006X in M100
We report the discovery of a light echo (LE) from the Type Ia supernova (SN) 2006X in the nearby galaxy M100. The presence of the LE is supported by analysis of both the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) images and the Keck optical spectrum that we obtained at ~300 days after maximum brightness. In the image procedure, both the radial-profile analysis and the point-spread function (PSF) subtraction method resolve significant excess emission at 2-5 ACS pixels (~0.05 -->''-0.13 -->'') from the center. In particular, the PSF-subtracted ACS images distinctly appear to have an extended, ringlike echo. Due to limitations of the image resolution, we cannot confirm any structure or flux within 2 ACS pixels from the SN. The late-time spectrum of SN 2006X can be reasonably fit with two components: a nebular spectrum of a normal SN Ia and a synthetic LE spectrum. Both image and spectral analysis show a rather blue color for the emission of the LE, suggestive of a small average grain size for the scattering dust. Using the Cepheid distance to M100 of 15.2 Mpc, we find that the dust illuminated by the resolved LE is ~27-170 pc from the SN. The echo inferred from the nebular spectrum appears to be more luminous than that resolved in the images (at the ~2 σ level), perhaps suggesting the presence of an inner echo at ''). It is not clear, however, whether this possible local echo was produced by a distinct dust component (i.e., the local circumstellar dust) or by a continuous, larger distribution of dust as with the outer component. Nevertheless, our detection of a significant echo in SN 2006X confirms that this supernova was produced in a dusty environment having small dust particles.
15159726
First results from the lick AGN monitoring project: The mass of the black hole in ARP 151
We have recently completed a 64 night spectroscopic monitoring campaign at the Lick Observatory 3 m Shane telescope with the aim of measuring the masses of the black holes in 13 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~106-107 M☉. We present here the first results from this project—the mass of the central black hole in Arp 151. Strong variability throughout the campaign led to an exceptionally clean Hβ lag measurement in this object of 4.25−0.66+0.68 days in the observed frame. Coupled with the width of the Hβ emission line in the variable spectrum, we determine a black hole mass of (7.1 ± 1.2) × 106 M☉, assuming the Onken et al. normalization for reverberation-based virial masses. We also find velocity-resolved lag information within the Hβ emission line which clearly shows infalling gas in the Hβ-emitting region. Further detailed analysis may lead to a full model of the geometry and kinematics of broad line region gas around the central black hole in Arp 151.
119510990
High pT hadron spectra in high-energy heavy-ion collisions
Abstract We calculate the hadron spectra in high-energy pp , pA and AA collisions within a pQCD parton model. Analyses of experimental data show that the modification of the spectra in pA and AA as compared to that in pp collisions is consistent with multiple parton scattering scenario and is dictated by the transition from absorptive soft interaction at low p T to incoherent hard parton scattering at high p T . This analysis not only sheds new light on the limits to the physics analysis based on thermal fire-ball models but also provides a more quantitative baseline results on which one can study the effects of parton energy loss in the hadron spectra at high p T .