•BioFire Respiratory Panel 2.1 SARS-CoV-2 assay high sensitivity and specificity.•Comparable performance to gold standard tests for low level viral RNA detection.•Rapid, sample-to-answer, syndromic ...testing for respiratory pathogens with SARS-CoV-2.
We evaluated the performance of the BioFire® Respiratory Panel 2.1 (RP2.1) in the detection of SARS CoV-2 in comparison against three other SARS CoV-2 EUA assays. In these studies, the RP2.1 panel had 98 % positive percent agreement (48/49) and 100 % negative percent agreement (49/49). Since 30 % of nasopharyngeal swab specimens have a SARS CoV-2 Ct >30 and thus detection of virus in low titers is clinically relevant, a sample with a high titer was diluted and each 10 fold dilution was tested in triplicate and compared against 6 other EUA approved SARS CoV-2 assays. These data suggested that the BioFire® RP2.1 panel, along with four other SARS CoV-2 assays (Roche cobas, Cepheid Xpert Xpress, BioFire® Defense COVID19, and NECoV19), consistently detected viral RNA at the 10−7 dilution. Overall, these studies suggest that the BioFire® RP2.1 assay can be used to detect acute cases of SARS CoV2 in addition to patients with low viral titer later in disease presentation.
We model the strong lensing effect in the galaxy cluster PSZ1 G311.65-18.48 (
z
= 0.443) with an improved version of the hybrid method WSLAP+. We extend the number of constraints by including the ...position of critical points, which are combined with the classic positional constraints of the lensed galaxies. We pay special attention to a transient candidate source (Tr) previously discovered in the giant Sunburst arc (
z
= 2.37). Our lens model predicts Tr to be within a fraction of an arcsecond from the critical curve, which has a larger magnification factor than previously found, but still not large enough to explain the observed flux and lack of counterimages. Possible candidate counterimages are discussed that would lower the magnification required to explain Tr, but extreme magnification factors (
μ
> 600) are still required, even in that case. The presence of a small mass perturber with a mass comparable to a dwarf galaxy (
M
∼ 10
8
M
⊙
) near the position of Tr is needed in order to explain the required magnification and morphology of the lensed galaxy. We discuss how the existence of this perturber could potentially be used to constrain models of dark matter. The large apparent brightness and unresolved nature of the magnified object implies a combination of extreme magnification and a very luminous and compact source (
r
< 0.4 pc). Possible candidates are discussed, including an hyperluminous star, a small group of stars, or an accretion disk around a relatively small supermassive black hole (SMBH). Based on spectral information and flux requirements, we argue that a luminous blue variable (LBV) star caught during an outburst is the most likely candidate. Owing to the extreme magnification and luminosity of this source, we dub it Godzilla.
ABSTRACT Supernova "Refsdal," multiply imaged by cluster MACS1149.5+2223, represents a rare opportunity to make a true blind test of model predictions in extragalactic astronomy, on a timescale that ...is short compared to a human lifetime. In order to take advantage of this event, we produced seven gravitational lens models with five independent methods, based on Hubble Space Telescope (HST) Hubble Frontier Field images, along with extensive spectroscopic follow-up observations by HST, the Very Large and the Keck Telescopes. We compare the model predictions and show that they agree reasonably well with the measured time delays and magnification ratios between the known images, even though these quantities were not used as input. This agreement is encouraging, considering that the models only provide statistical uncertainties, and do not include additional sources of uncertainties such as structure along the line of sight, cosmology, and the mass sheet degeneracy. We then present the model predictions for the other appearances of supernova "Refsdal." A future image will reach its peak in the first half of 2016, while another image appeared between 1994 and 2004. The past image would have been too faint to be detected in existing archival images. The future image should be approximately one-third as bright as the brightest known image (i.e., mag at peak and mag six months before peak), and thus detectable in single-orbit HST images. We will find out soon whether our predictions are correct.
Microlenses with typical stellar masses (a few M⊙) have traditionally been disregarded as potential sources of gravitational lensing effects at LIGO/Virgo frequencies, since the time delays are often ...much smaller than the inverse of the frequencies probed by LIGO/Virgo, resulting in negligible interference effects at LIGO/Virgo frequencies. While this is true for isolated microlenses in this mass regime, we show how, under certain circumstances and for realistic scenarios, a population of microlenses (for instance stars and remnants from a galaxy halo or from the intracluster medium) embedded in a macromodel potential (galaxy or cluster) can conspire together to produce time delays of order one millisecond, which would produce significant interference distortions in the observed strains. At sufficiently large magnification factors (of several hundred), microlensing effects should be common in gravitationally lensed gravitational waves. We explored the regime where the predicted signal falls in the frequency range probed by LIGO/Virgo. We find that stellar mass microlenses, permeating the lens plane, and near critical curves, can introduce interference distortions in strongly lensed gravitational waves. Lensed events with negative parity, or saddle points (which have never before been studied in the context of gravitational waves), and that take place near caustics of macromodels, are more likely to produce measurable interference effects at LIGO/Virgo frequencies. This is the first study that explores the effect of a realistic population of microlenses, including a macromodel, on strongly lensed gravitational waves.
We present a comprehensive mass reconstruction of the rich galaxy cluster CI 0024+17 at z unk 0.4 from ACS data, unifying both strong- and weak-lensing constraints. The weak-lensing signal from a ...dense distribution of background galaxies ( similar to 120 arcmin super(-2)) across the cluster enables the derivation of a high-resolution parameter-free mass map. The strongly lensed objects tightly constrain the mass structure of the cluster inner region on an absolute scale, breaking the mass-sheet degeneracy. The mass reconstruction of CI 0024+17 obtained In such a way is remarkable. It reveals a ringlike dark matter substructure at r similar to 75" surrounding a soft, dense core at r unk 50 unk. We interpret this peculiar substructure as the result of a high-speed line-of-sight collision of two massive clusters similar to 1-2 Gyr ago. Such an event is also indicated by the cluster velocity distribution. Our numerical simulation with purely collisionless particles demonstrates that such density ripples can arise by radially expanding, decelerating particles that originally comprised the precollision cores. CI 0024+17 can be likened to the bullet cluster 1E 0657-56, but viewed along the collision axis at a much later epoch. In addition, we show that the long-standing mass discrepancy for CI 0024+17 between X-ray and lensing can be resolved by treating the cluster X-ray emission as coming from a superposition of two X-ray systems. The cluster's unusual X-ray surface brightness profile that requires a two isothermal sphere description supports this hypothesis.
We present a free-form model of SMACS0723, the first cluster observed with JWST. This model does not make any strong assumptions on the distribution of mass (mostly made up of dark matter) in the ...cluster and we use it to study the possible correlation between dark matter with the intracluster light and distribution of globular clusters (GCs). To explore the uncertainty in mass modeling, we derived three lens models based on spectroscopically confirmed systems and new candidate systems with redshifts predicted by the lens model derived from the spectroscopic systems. We find that beyond the radius of influence for the brightest cluster galaxy (BCG), the total mass does not trace the intracluster light (ICL), implying the need for a dark component (dark matter). Two loop-like structures observed in the intracluster light do not have any obvious correspondence with the total mass (of mostly dark matter) distribution. The radial profiles of the ICL and the distribution of GCs are similar to each other, but they are steeper than the profile of the lens model. More specifically, we find that the total mass is shallower by 1 dex in log scale than both ICL and GC profiles. This is in excellent agreement with current
N
-body simulations of cold dark matter.
The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) will scan thousands of square degrees of the northern sky with a unique set of 56 filters using the dedicated 2.55 m ...Javalambre Survey Telescope (JST) at the Javalambre Astrophysical Observatory. Prior to the installation of the main camera (4.2 deg
2
field-of-view with 1.2 Gpixels), the JST was equipped with the JPAS-Pathfinder, a one CCD camera with a 0.3 deg
2
field-of-view and plate scale of 0.23 arcsec pixel
−1
. To demonstrate the scientific potential of J-PAS, the JPAS-Pathfinder camera was used to perform miniJPAS, a ∼1 deg
2
survey of the AEGIS field (along the Extended Groth Strip). The field was observed with the 56 J-PAS filters, which include 54 narrow band (
FWHM
∼ 145 Å) and two broader filters extending to the UV and the near-infrared, complemented by the
u
,
g
,
r
,
i
SDSS broad band filters. In this miniJPAS survey overview paper, we present the miniJPAS data set (images and catalogs), as we highlight key aspects and applications of these unique spectro-photometric data and describe how to access the public data products. The data parameters reach depths of mag
AB
≃ 22−23.5 in the 54 narrow band filters and up to 24 in the broader filters (5
σ
in a 3″ aperture). The miniJPAS primary catalog contains more than 64 000 sources detected in the
r
band and with matched photometry in all other bands. This catalog is 99% complete at
r
= 23.6 (
r
= 22.7) mag for point-like (extended) sources. We show that our photometric redshifts have an accuracy better than 1% for all sources up to
r
= 22.5, and a precision of ≤0.3% for a subset consisting of about half of the sample. On this basis, we outline several scientific applications of our data, including the study of spatially-resolved stellar populations of nearby galaxies, the analysis of the large scale structure up to
z
∼ 0.9, and the detection of large numbers of clusters and groups. Sub-percent redshift precision can also be reached for quasars, allowing for the study of the large-scale structure to be pushed to
z
> 2. The miniJPAS survey demonstrates the capability of the J-PAS filter system to accurately characterize a broad variety of sources and paves the way for the upcoming arrival of J-PAS, which will multiply this data by three orders of magnitude.
The first
James Webb
Space Telescope (JWST) data on the massive colliding cluster
El Gordo
allow for 23 known families of multiply lensed images to be confirmed and for eight new members of these ...families to be identified. Based on these families, which have been confirmed spectroscopically by MUSE, we derived an initial lens model. This model guided the identification of 37 additional families of multiply lensed galaxies, among which 28 are entirely new systems, and nine were previously known. The initial lens model determined geometric redshifts for the 37 new systems. The geometric redshifts agree reasonably well with spectroscopic or photometric redshifts when those are available. The geometric redshifts enable two additional models that include all 60 families of multiply lensed galaxies spanning a redshift range 2 <
z
< 6. The derived dark-matter distribution confirms the double-peak configuration of mass found by earlier work with the southern and northern clumps having similar masses. We confirm that El Gordo is the most massive known cluster at
z
> 0.8 and has an estimated virial mass close the maximum mass allowed by standard cosmological models. The JWST images also reveal the presence of small-mass perturbers that produce small lensing distortions. The smallest of these is consistent with being a dwarf galaxy at
z
= 0.87 and has an estimated mass of 3.8 × 10
9
M
⊙
, making it the smallest substructure found at
z
> 0.5. The JWST images also show several candidate caustic-crossing events. One of them is detected at high significance at the expected position of the critical curve and is likely a red supergiant star at
z
= 2.1878. This would be the first red supergiant found at cosmological distances. The cluster lensing should magnify background objects at
z
> 6, making more of them visible than in blank fields of a similar size, but there appears to be a deficiency of such objects.
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