Abstract
We report on the serendipitous discovery of three transient millimeter-wave sources using data from the Atacama Cosmology Telescope. The first, detected at R.A
.
= 273.8138, decl. = −49.4628 ...at ∼50
σ
total, brightened from less than 5 mJy to at least 1100 mJy at 150 GHz with an unknown rise time shorter than 13 days, during which the increase from 250 mJy to 1100 mJy took only 8 minutes. Maximum flux was observed on 2019 November 8. The source’s spectral index in flux between 90–150 GHz was positive,
α
= 1.5 ± 0.2. The second, detected at R.A. = 105.1584, decl
.
= −11.2434 at ∼20
σ
total, brightened from less than 20 mJy to at least 300 mJy at 150 GHz with an unknown rise time shorter than 8 days. Maximum flux was observed on 2019 December 15. Its spectral index was also positive,
α
= 1.8 ± 0.2. The third, detected at R.A
.
= 301.9952, decl. = 16.1652 at ∼40
σ
total, brightened from less than 8 mJy to at least 300 mJy at 150 GHz over a day or less but decayed over a few days. Maximum flux was observed on 2018 September 11. Its spectrum was approximately flat, with a spectral index of
α
= −0.2 ± 0.1. None of the sources were polarized to the limits of these measurements. The two rising-spectrum sources are coincident in position with M and K stars, while the third is coincident with a G star.
Context. The thermal Sunyaev-Zeldovich (SZ) effect presents a relatively new tool for characterizing galaxy cluster merger shocks, traditionally studied through X-ray observations. Widely regarded as ...the “textbook example” of a cluster merger bow shock, the western, most-prominent shock front in the Bullet Cluster (1E0657-56) represents the ideal test case for such an SZ study. Aims. We aim to characterize the shock properties using deep, high-resolution interferometric SZ effect observations in combination with priors from an independent X-ray analysis. Methods. Our analysis technique relies on the reconstruction of a parametric model for the SZ signal by directly and jointly fitting data from the Atacama Large Millimeter/submillimeter Array (ALMA) and Atacama Compact Array (ACA) in Fourier space. Results. The ALMA+ACA data are primarily sensitive to the electron pressure difference across the shock front. To estimate the shock Mach number ℳ, this difference can be combined with the value for the upstream electron pressure derived from an independent Chandra X-ray analysis. In the case of instantaneous electron-ion temperature equilibration, we find ℳ = 2.08−0.12+0.12 M = 2 . 08 − 0.12 + 0.12 $ \mathcal{M}=2.08^{+0.12}_{-0.12} $ , in ≈ 2.4σ tension with the independent constraint from Chandra, MX = 2.74 ± 0.25. The assumption of purely adiabatic electron temperature change across the shock leads to ℳ = 2.53−0.25+0.33 M = 2 . 53 − 0.25 + 0.33 $ \mathcal{M}=2.53^{+0.33}_{-0.25} $ , in better agreement with the X-ray estimate ℳX = 2.57 ± 0.23 derived for the same heating scenario. Conclusion. We have demonstrated that interferometric observations of the thermal SZ effect provide constraints on the properties of the shock in the Bullet Cluster that are highly complementary to X-ray observations. The combination of X-ray and SZ data yields a powerful probe of the shock properties, capable of measuring ℳ and addressing the question of electron-ion equilibration in cluster shocks. Our analysis is however limited by systematics related to the overall cluster geometry and the complexity of the post-shock gas distribution. To overcome these limitations, a simultaneous, joint-likelihood analysis of SZ and X-ray data is needed.
The aim of primary palatoplasty is to achieve optimum speech with minimal morbidity. Symptomatic fistulae are well-recognised complications of palatoplasty and may require additional surgical ...intervention, increasing the burden of care. Our aims were to better understand fistula experience in our unit and compare fistula rates between an established consultant and a newly appointed training interface group (TIG) trained consultant. Post-operative fistulae were prospectively and independently recorded by Cleft Clinical Nurse Specialists as part of routine 6-week post-operative reviews. Cleft type and intra-operative hard-soft palate junction (HSPJ) width were prospectively recorded by operating surgeons. Data were collated and analysed using Microsoft Excel. Between 1 January 2014 and 31 December 2018, 250 primary palatoplasties were performed. The overall fistula rate was 8% (0% SMCP, ICP 7%, UCLP 8%, BCLP 22%). Fistulae clustered in clefts with a mid-range HSPJ width of 12–16 mm. Numerically, fistula rates remained similar over time despite increased unit activity (doubling of primary surgeries in 2017 and 2018). There was no significant difference in fistulae rates between surgeons (P > 0.05). Overall fistulae rate compared favourably with published data. TIG fellowships were designed in the context of cleft surgery to address issues relating to steep operative learning curves. These data demonstrate that results from a newly appointed TIG-trained surgeon are comparable to that of an established TIG-trained surgeon. Data also suggest surgeons should be aware of the risk of fistulae in the mid-range palatal defect and in HSPJ widths of 12–16 mm.
We present a catalog of 510 radio-loud active galactic nuclei (AGNs, primarily blazars) and 287 dusty star-forming galaxies (DSFGs) detected by the Atacama Cosmology Telescope at significance in ...frequency bands centered on 148 GHz (2 mm), 218 GHz (1.4 mm), and 277 GHz (1.1 mm), from a 480 deg2 strip centered at R.A. 00h on the celestial equator with additional 360 deg2 shallower auxiliary fields at other longitudes. The combination of the deepest available 218 GHz wide-field imaging, our 277 GHz data, and multiband filtering results in the most sensitive wide-field millimeter-wave DSFG selection to date, with rms noise level referenced to 218 GHz reaching below 2 mJy. We have developed new techniques to remove Galactic contamination (including evidence for CO (2−1) line emission) from the extragalactic catalog, yielding a catalog of 321 Galactic sources in addition to the extragalactic catalog. We employ a new flux debiasing method that accounts for the heterogeneous sample selection in the presence of Galactic cuts. We present the spectral properties and source counts of the AGNs and DSFGs. The DSFG spectra depart from the Rayleigh-Jeans regime of an optically thin modified blackbody between 218 and 277 GHz, consistent with optically thick emission or an additional cold dust component. For AGNs with 148 and 218 GHz flux density >50 mJy, we estimate the interyear rms fractional deviation in flux density due to source variability to be 40% with a 0.98 interband correlation coefficient. We provide source counts for AGNs in the range of 8-2870 mJy and for DSFGs in the range of 8-90 mJy. Our DSFG counts probe both the brighter, lensed population and the fainter, unlensed population. At 277 GHz we report the first measurements of source counts at these flux densities, finding an excess above most model count predictions. Finally, we present 30 of the brightest DSFGs that were selected for multifrequency study as candidate high-z lensed systems.
We use Atacama Cosmology Telescope (ACT) observations at 98 GHz (2015–2019), 150 GHz (2013–2019), and 229 GHz (2017–2019) to perform a blind shift-and-stack search for Planet 9. The search explores ...distances from 300 au to 2000 au and velocities up to 6\farcm3 per year, depending on the distance (r). For a 5 Earth-mass Planet 9 the detection limit varies from 325 au to 625 au, depending on the sky location. For a 10 Earth-mass planet the corresponding range is 425 au to 775 au. The predicted aphelion and most likely location of the planet corresponds to the shallower end of these ranges. The search covers the whole 18,000 square degrees of the ACT survey. No significant detections are found, which is used to place limits on the millimeter-wave flux density of Planet 9 over much of its orbit. Overall we eliminate roughly 17% and 9% of the parameter space for a 5 and 10 Earth-mass Planet 9, respectively. These bounds approach those of a recent INPOP19a ephemeris-based analysis, but do not exceed it. We also provide a list of the 10 strongest candidates from the search for possible follow-up. More generally, we exclude (at 95% confidence) the presence of an unknown solar system object within our survey area brighter than 4–12 mJy (depending on position) at 150 GHz with current distance 300 au < r < 600 au and heliocentric angular velocity 1\farcm5 per yr < v x (500au/r) < 2\farcs3 per yr, corresponding to low-to-moderate eccentricities. These limits worsen gradually beyond 600 au, reaching 5–15 mJy by 1500 au.
The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has made 1 deg2, deep, confusion-limited maps at three different bands, centered on the Great Observatories Origins Deep Survey South ...Field. By calculating the covariance of these maps with catalogs of 24 Delta *mm sources from the Far-Infrared Deep Extragalactic Legacy Survey, we have determined that the total submillimeter intensities are 8.60 +/- 0.59, 4.93 +/- 0.34, and 2.27 +/- 0.20 nW m-2 sr-1 at 250, 350, and 500 Delta *mm, respectively. These numbers are more precise than previous estimates of the cosmic infrared background (CIB) and are consistent with 24 Delta *mm-selected galaxies generating the full intensity of the CIB. We find that the fraction of the CIB that originates from sources at z >= 1.2 increases with wavelength, with 60% from high-redshift sources at 500 Delta *mm. At all BLAST wavelengths, the relative intensity of high-z sources is higher for 24 Delta *mm-faint sources than that for 24 Delta *mm-bright sources. Galaxies identified as active galactic nuclei (AGNs) by their Infrared Array Camera colors are 1.6-2.6 times brighter than the average population at 250-500 Delta *mm, consistent with what is found for X-ray-selected AGNs. BzK-selected galaxies are found to be moderately brighter than typical 24 Delta *mm-selected galaxies in the BLAST bands. These data provide high-precision constraints for models of the evolution of the number density and intensity of star-forming galaxies at high redshift.
ABSTRACT
Compact sources can cause scatter in the scaling relationships between the amplitude of the thermal Sunyaev–Zel’dovich Effect (tSZE) in galaxy clusters and cluster mass. Estimates of the ...importance of this scatter vary – largely due to limited data on sources in clusters at the frequencies at which tSZE cluster surveys operate. In this paper, we present 90 GHz compact source measurements from a sample of 30 clusters observed using the MUSTANG2 instrument on the Green Bank Telescope. We present simulations of how a source’s flux density, spectral index, and angular separation from the cluster’s centre affect the measured tSZE in clusters detected by the Atacama Cosmology Telescope (ACT). By comparing the MUSTANG2 measurements with these simulations we calibrate an empirical relationship between 1.4 GHz flux densities from radio surveys and source contamination in ACT tSZE measurements. We find 3 per cent of the ACT clusters have more than a 20 per cent decrease in Compton-y but another 3 per cent have a 10 per cent increase in the Compton-y due to the matched filters used to find clusters. As sources affect the measured tSZE signal and hence the likelihood that a cluster will be detected, testing the level of source contamination in the tSZE signal using a tSZE-selected catalogue is inherently biased. We confirm this by comparing the ACT tSZE catalogue with optically and X-ray-selected cluster catalogues. There is a strong case for a large, high-resolution survey of clusters to better characterize their source population.
The properties of galaxy clusters as a function of redshift can be utilized as an important cosmological tool. We present initial results from a program of follow-up observations of the ...Sunyaev-Zeldovich effect (SZE) in high-redshift galaxy clusters detected by the Massive and Distant Clusters of WISE Survey (MaDCoWS) which uses infrared data from the Wide-field Infrared Survey (WISE) instrument. Using typical on-source integration times of 3-4 hr per cluster, MUSTANG2 on the Green Bank Telescope was able to measure strong detections of SZE decrements and statistically significant masses on 14 out of 16 targets. On the remaining two, weaker (3.7 ) detections of the SZE signal and strong upper limits on the masses were obtained. In this paper we present masses and pressure profiles of each target and outline the data analysis used to recover these quantities. Of the clusters with strong detections, three show significantly flatter pressure profiles while, from the MUSTANG2 data, five others show signs of disruption at their cores. However, outside of the cores of the clusters, we were unable to detect significant amounts of asymmetry. Finally, there are indications that the relationship between optical richness used by MaDCoWS and SZE-inferred mass may be significantly flatter than indicated in previous studies.
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