Infrared studies of supernova remnants with the IRAS

A comparative study of the infrared and X-ray fluxes and morphologies of supernova remnants (SNR) can yield valuable information on their evolution and on their interaction with the smbient interstellar medium (ISM)

A Tentative Detection of the Cosmic Infrared Background at 3.5 microns from COBE/DIRBE Observations

Foreground emission and scattered light from interplanetary dust (IPD) particles and emission from Galactic stellar sources are the greatest obstacles for determining the cosmic infrared background (CIB) from diffuse sky measurements in the ~ 1 to 5 micron range. We use ground-based observational limits on the K-band intensity of the CIB in conjunction with skymaps obtained by the Diffuse Infrared Background Experiment (DIRBE) on the COBE satellite to reexamine the limits on the CIB at 1.25, 3.5, and 4.9 microns. Adopting a CIB intensity of 7.4 nW m-2 sr-1 at 2.2 microns, and using the 2.2 micron DIRBE skymap from which the emission from IPD cloud has been subtracted, we create a spatial template of the Galactic stellar contribution to the diffuse infrared sky. This template is then used to subtract the contribution of the diffuse Galactic stellar emission from the IPD-emission-subtracted DIRBE skymaps. The DIRBE 100 micron data are used to estimate the small contribution of emission from interstellar dust at 3.5 and 4.9 microns. Our method significantly reduces the errors associated with the subtraction of Galactic starlight, leaving only the IPD emission component as the primary obstacle for the detection of the CIB at these wavelengths. This analysis leads to a tentative detection of the CIB at 3.5 microns. The cosmological implications of these results are discussed in the paper.Comment: 8 pages, AASTeX, 2 embedded EPS figures. Accepted for publication in ApJ Letter

Cadherin-5: a biomarker for metastatic breast cancer with optimum efficacy in oestrogen receptor-positive breast cancers with vascular invasion

Background: A glycoproteomic study has previously shown cadherin-5 (CDH5) to be a serological marker of metastatic breast cancer when both protein levels and glycosylation status were assessed. In this study we aimed to further validate the utility of CDH5 as a biomarker for breast cancer progression. Methods: A nested case–control study of serum samples from breast cancer patients, of which n=52 had developed a distant metastatic recurrence within 5 years post-diagnosis and n=60 had remained recurrence-free. ELISAs were used to quantify patient serum CDH5 levels and assess glycosylation by Helix pomatia agglutinin (HPA) binding. Clinicopathological, treatment and lifestyle factors associated with metastasis and elevated biomarker levels were identified. Results: Elevated CDH5 levels (P=0.028) and ratios of CDH5:HPA binding (P=0.007) distinguished patients with metastatic disease from those that remained metastasis-free. Multivariate analysis showed that the association between CDH5:HPA ratio and the formation of distant metastases was driven by patients with oestrogen receptor (ER+) positive cancer with vascular invasion (VI+). Conclusions: CDH5 levels and the CDH5 glycosylation represent biomarker tests that distinguish patients with metastatic breast cancer from those that remain metastasis-free. The test reached optimal sensitivity and specificity in ER-positive cancers with vascular invasion

The Resolved Near-Infrared Extragalactic Background

We present a current best estimate of the integrated near-infrared (NIR) extragalactic background light (EBL) attributable to resolved galaxies in J, H, and Ks. Our results in units of nW m-2 sr-1 are 11.7+5.6 -2.6 in J, 11.5+4.5 -1.5 in H and 10.0+2.8 -0.8 in Ks. We derive these new limits by combining our deep wide-field NIR photometry from five widely separated fields with other studies from the literature to create a galaxy counts sample that is highly complete and has good counting statistics out to JHKs ~ 27-28. As part of this effort we present new ultradeep Ks-band galaxy counts from 22 hours of observations with the Multi Object Infrared Camera and Spectrograph (MOIRCS) instrument on the Subaru Telescope. We use this MOIRCS Ks-band mosaic to estimate the total missing flux from sources beyond our detection limits. Our new limits to the NIR EBL are in basic agreement with, but 10 - 20% higher than previous estimates, bringing them into better agreement with estimates of the total NIR EBL (resolved + unresolved sources) obtained from TeV gamma-ray opacity measurements and recent direct measurements of the total NIR EBL. We examine field to field variations in our photometry to show that the integrated light from galaxies is isotropic to within uncertainties, consistent with the expected large-scale isotropy of the EBL. Our data also allow for a robust estimate of the NIR light from Galactic stars, which we find to be 14.7 +/- 2.4 in J, 10.1 +/- 1.9 in H and 7.6 +/- 1.8 in Ks in units of nW m-2 sr-1.Comment: Accepted to Ap

Properties and Spatial Distribution of Dust Emission in the Crab Nebula

The nature and quantity of dust produced in supernovae (SNe) is still poorly understood. Recent IR observations of freshly-formed dust in supernova remnants (SNRs) have yielded significantly lower dust masses than predicted by theoretical models and observations high-redshift galaxies. The Crab Nebula's pulsar wind is thought to be sweeping up freshly-formed SN dust along with the SN ejecta. The evidence for this dust was found in the form of an IR bump in the integrated spectrum of the Crab and in extinction against the synchrotron nebula that revealed the presence of dust in the filament cores. We present the first spatially-resolved emission spectra of dust in the Crab Nebula acquired with the Spitzer Space Telescope. The IR spectra are dominated by synchrotron emission and show forbidden line emission from both sides of the expanding nebula, including emission from [S III], [Si II], [Ne II], [Ne III], [Ne V], [Ar III], [Ar V], [Fe II], and [Ni II]. We extrapolated a synchrotron spectral data cube from the Spitzer 3.6 and 4.5 micron images, and subtracted this contribution from our 15-40 micron spectral data to produce a map of the residual continuum emission from dust. The emission appears to be concentrated along the ejecta filaments and is well described by astronomical silicates at an average temperature of 65 K. The estimated mass of dust in the Crab Nebula is 0.008 solar masses

Strong New Constraints on the Extragalactic Background Light in the Near- to Mid-IR

Direct measurements of the extragalactic background light (EBL) in the near-IR to mid-IR waveband are extremely difficult due to an overwhelming foreground from the zodiacal light that outshines the faint cosmological diffuse radiation field by more than an order of magnitude. Indirect constraints on the EBL are provided by gamma-ray observations of AGN. Using the combination of the Fermi Gamma-Ray Space Telescope together with the current generation of ground-based air Cherenkov telescopes (H.E.S.S., MAGIC, and VERITAS) provides unprecedented sensitivity and spectral coverage for constraining the EBL in the near- to mid-IR. In this paper we present new limits on the EBL based on the analysis of the broad-band spectra of a select set of gamma-ray blazars covering 200 MeV to several TeV. The EBL intensity at 15 microns is constrained to be 1.36 +/- 0.58 nW m^-2 sr^-1. We find that the fast evolution and baseline EBL models of Stecker et al. (2006), as well as the model of Kneiske et al. (2004), predict significantly higher EBL intensities in the mid-IR (15 microns) than is allowed by the constraints derived here. In addition, the model of Franceschini et al. (2008) and the fiducial model of Dominguez et al. (2011) predict near- to mid-IR ratios smaller than that predicted by our analysis. Namely, their intensities in the near-IR are too low while their intensities in the mid-IR are marginally too high. All of the aforementioned models are inconsistent with our analysis at the >3 sigma level.Comment: 37 pages, 13 figures, updated subject headings, accepted by Ap