Far-Infrared Emission From E and E/S0 Galaxies

Studies of cold material through IRAS 60um and 100um observations indicated that half of ordinary E and E/S0 galaxies were detected above the 3 sigma level, indicating that cold gas is common, although no correlation was found between the optical and far- infrared fluxes. Most detections were near the instrumental threshold, and given an improved understanding of detection confidence, we reconsider the 60um and 100um detection rate. After excluding active galactic nuclei, peculiar systems, and background contamination, only 15 non-peculiar E and E/S0 galaxies from the RSA catalog are detected above the 98% confidence level, about 12% of the sample. An unusually high percentage of these 15 galaxies possess cold gas (HI, CO) and optical emission lines (Halpha), supporting the presence of gas cooler than 10E4 K. The 60um to 100um flux ratios imply a median dust temperature for the sample of 30 K, with a range of 23-38 K. These detections define the upper envelope of the optical to far-infrared relationship, F_fir propto F_B^0.24+/-0.08, showing that optically bright objects are also brighter in the infrared, although with considerable dispersion. A luminosity correlation is present with L_fir propto L_B^1.65+/-0.28, but the dust temperature is uncorrelated with luminosity. Models that contain large dust grains composed of amorphous carbon plus silicates come close to reproducing the typical 60um to 100um flux ratios, the far-infrared luminosity, and the L_fir - L_B relationship.Comment: 10 postscript pages, 2 tables, and 2 figure

Radio Sources in Galaxy Clusters at 28.5 GHz

We present serendipitous detections of radio sources at 28.5 GHz (1 cm), which resulted from our program to image thermal Sunyaev-Zeldovich (SZ) effect in 56 galaxy clusters. We find 64 radio sources with fluxes down to 0.4 mJy, and within 250 arcseconds from the pointing centers. The spectral indices (S ~ \nu^-\alpha) of 54 sources with published low frequency flux densities range from -0.6 to 2 with a mean of 0.77, and a median of 0.84. Extending low frequency surveys of radio sources towards galaxy clusters CL 0016+16, Abell 665, and Abell 2218 to 28.5 GHz, and selecting sources with 1.4 GHz flux density greater than 7 mJy to form an unbiased sample, we find a mean spectral index of 0.71 and a median of 0.71. We find 4 to 7 times more sources predicted from a low frequency survey in areas without galaxy clusters. This excess cannot be accounted for by gravitational lensing of a background radio population by cluster potentials, indicating most of the detected sources are associated with galaxy clusters. For the cluster Abell 2218, the presence of unsubtracted radio sources with 28.5 GHz flux densities less than 0.5 mJy, can only contribute to temperature fluctuations at a level of 10 to 25 \muK. The corresponding error due to radio point source contamination in the Hubble constant derived through a combined analysis of 28.5 GHz SZ images and X-ray emission observations ranges from 1% to 6%.Comment: 18 pages, 8 figures, to appear in April 1998 issue of A

Masses of high-redshift clusters via SZ effect observations

Journal ArticleWe present Sunyaev-Zel'dovich Effect (SZE) observations of distant, highly X-ray luminous clusters of galaxies. We use the SZE data to constrain their total masses, independent of X-ray observations. To do this, we assume the clusters have the same gas mass fraction as that derived from SZE measurements of a sample of known massive clusters, and then infer each cluster's mass from its SZE data. In the systems with published X-ray temperatures, we find good agreement between our SZE-derived temperatures and those inferred from X-ray spectroscopy; in the system without X-ray derived temperatures, the SZE data provide the first confirmation that it is indeed a massive system. The abundance of clusters at high redshift is critically sensitive to the values of the cosmological parameters and so the demonstrated ability to determine cluster temperatures and masses from SZE observations independent of X-ray data illustrates the power of using deep SZE surveys to probe the distant universe

Oxazolidinone resistance-associated genes cfr and optrA in MDR CoNS from healthy pigs in Italy

BACKGROUND: Oxazolidinones are relatively novel antibiotics used exclusively in human medicine as last resort drugs for resistant pathogens like MRSA, vancomycin-resistant enterococci and penicillin-resistant Streptococcus pneumoniae. However, in the last two decades, oxazolidinone resistance genes cfr and optrA have been sporadically reported worldwide in Staphylococcus spp. of livestock origin.(1) These genes can be chromosomal, but they are often transferable through mobile genetic elements, especially plasmids.(2) In Italy, they have been recently detected in enterococci of swine origin.(3) OBJECTIVES: To uncover the presence of cfr and optrA genes in methicillin-resistant CoNS (MRCoNS) originating from swine nasal swabs sampled in a high farm-density area of northwestern Italy. Healthy pigs were sampled from three productive stages (finishing, weaners and sows). After isolating pure cultures, selected staphylococci (n = 27), resulted methicillin-resistant from previous mecA identification, were phenotypically tested through Kirby–Bauer disc diffusion method for the antibiotics clindamycin, doxycycline, erythromycin, enrofloxacin, florfenicol, gentamicin, linezolid, tetracycline, tiamulin and trimethoprim/sulfamethoxazole (EUCAST v.11.0 guidelines for linezolid disc, CLSI VET08 for the other antibiotics). MIC through Etest (Liofilchem®, Roseto degli Abbruzzi, Teramo, Italy) was used for the antibiotic ceftaroline. RESULTS: All the chosen MRCoNS were MDR (MDR CoNS), as they were phenotypically resistant to more than three antibiotic classes. No strain was positive for ceftaroline resistance. Since linezolid resistance was recovered in six samples, we decided to perform PCR for the cfr gene (746 bp), which was detected in Staphylococcus sciuri from a piglet (GenBank accession number OL412394), and optrA (1395 bp), which was recovered in Staphylococcus pasteuri from a finisher, S. sciuri from a sow and Staphylococcus cohnii from a weaner (GenBank accession numbers OM165030, OM165031 and OM165032). Sanger sequencing confirmed PCR result for cfr, with 100% identity with the cfr gene detected from a clinical Italian isolate of MRSA (MH746818), and for optrA gene, which had 100% identity with the optrA previously found in a swine Italian Enterococcus faecium strain (MT723958). As far as we know, this is the first time that a cfr gene has been detected in S. sciuri from a nasal sample of animal origin in Italy. Furthermore, optrA was never detected in S. pasteuri and S. cohnii strains. CONCLUSIONS: These results are relevant from a One Health perspective, as they underline the need for oxazolidinone resistance monitoring, not only in human medicine, but also at farm level. In this way, it will be easier to prevent the dissemination of this resistance to human community and hospitals, where oxazolidinones are considered last-resort antibiotics. Furthermore, they remind the importance of surveillance of antibiotic usage in pigs, as cfr and optrA resistance in staphylococci can be elicited using certain antibiotics, like phenicols, due to cross-resistance to this antibiotic class

A Deep Chandra Observation of the Distant Galaxy Cluster MS1137.5+6625

We present results from a deep Chandra observation of MS1137.5+66, a distant (z=0.783) and massive cluster of galaxies. Only a few similarly massive clusters are currently known at such high redshifts; accordingly, this observation provides much-needed information on the dynamical state of these rare systems. The cluster appears both regular and symmetric in the X-ray image. However, our analysis of the spectral and spatial X-ray data in conjunction with interferometric Sunyaev-Zel'dovich effect data and published deep optical imaging suggests the cluster has a fairly complex structure. The angular diameter distance we calculate from the Chandra and Sunyaev-Zel'dovich effect data assuming an isothermal, spherically symmetric cluster implies a low value for the Hubble constant for which we explore possible explanations.Comment: 16 pages, 6 figures, submitted to Ap

Drone-based, Boost-Phase Intercept of North Korean ICBMs

North Korea currently has an adversarial relationship with the United States and has successfully tested both nuclear weapons and intercontinental-range ballistic missiles (ICBMs) capable of striking the continental United States.1 There are several ways the United States could attempt to address the threat posed by North Korea’s nuclear-armed ICBMs. Historically, the United States has relied on a policy of projecting military strength, fostering strong alliances, and maintaining a credible threat of retaliation to deter adversaries, including those with nuclear weapons, from initiating hostilities. Some have argued that this approach has been instrumental in preventing conflict between nuclear-armed nations, including North Korea, since the 1940s.2 In a crisis, the United States could also attempt to address this threat by preempting an attack. Alternatively, the United States could attempt to intercept and disable attacking ICBMs or their warheads in flight. It is this latter approach that is the focus of this work. Public demonstration of such a defensive capability would contribute to deterring a missile attack by showing that it is unlikely to succeed

Determining the Cosmic Distance Scale from Interferometric Measurements of the Sunyaev-Zel'dovich Effect

We determine the distances to 18 galaxy clusters with redshifts ranging from z~0.14 to z~0.78 from a maximum likelihood joint analysis of 30 GHz interferometric Sunyaev-Zel'dovich effect (SZE) and X-ray observations. We model the intracluster medium (ICM) using a spherical isothermal beta model. We quantify the statistical and systematic uncertainties inherent to these direct distance measurements, and we determine constraints on the Hubble parameter for three different cosmologies. These distances imply a Hubble constant of 60 (+4, -4) (+13, -18) km s-1 Mpc-1 for an Omega_M = 0.3, Omega_Lambda = 0.7 cosmology, where the uncertainties correspond to statistical followed by systematic at 68% confidence. With a sample of 18 clusters, systematic uncertainties clearly dominate. The systematics are observationally approachable and will be addressed in the coming years through the current generation of X-ray satellites (Chandra & XMM-Newton) and radio observatories (OVRO, BIMA, & VLA). Analysis of high redshift clusters detected in future SZE and X-ray surveys will allow a determination of the geometry of the universe from SZE determined distances.Comment: ApJ Submitted; 40 pages, 9 figures (fig 3 B&W for size constraint), 13 tables, uses emulateapj5 styl