59 research outputs found
CMZoom: Survey Overview and First Data Release
We present an overview of the CMZoom survey and its first data release.
CMZoom is the first blind, high-resolution survey of the Central Molecular Zone
(CMZ; the inner 500 pc of the Milky Way) at wavelengths sensitive to the
pre-cursors of high-mass stars. CMZoom is a 500-hour Large Program on the
Submillimeter Array (SMA) that mapped at 1.3 mm all of the gas and dust in the
CMZ above a molecular hydrogen column density of 10^23 cm^-2 at a resolution of
~3" (0.1 pc). In this paper, we focus on the 1.3 mm dust continuum and its data
release, but also describe CMZoom spectral line data which will be released in
a forthcoming publication. While CMZoom detected many regions with rich and
complex substructure, its key result is an overall deficit in compact
substructures on 0.1 - 2 pc scales (the compact dense gas fraction: CDGF). In
comparison with clouds in the Galactic disk, the CDGF in the CMZ is
substantially lower, despite having much higher average column densities. CMZ
clouds with high CDGFs are well-known sites of active star formation. The
inability of most gas in the CMZ to form compact substructures is likely
responsible for the dearth of star formation in the CMZ, surprising considering
its high density. The factors responsible for the low CDGF are not yet
understood but are plausibly due to the extreme environment of the CMZ, having
far-reaching ramifications for our understanding of the star formation process
across the cosmos.Comment: Accepted for Publication in ApJ
CMZoom III: Spectral Line Data Release
We present an overview and data release of the spectral line component of the
SMA Large Program, \textit{CMZoom}. \textit{CMZoom} observed CO(2-1),
CO(2-1) and CO(2-1), three transitions of HCO, several
transitions of CHOH, two transitions of OCS and single transitions of SiO
and SO, within gas above a column density of N(H)\,cm
in the Central Molecular Zone (CMZ; inner few hundred pc of the Galaxy). We
extract spectra from all compact 1.3\,mm \emph{CMZoom} continuum sources and
fit line profiles to the spectra. We use the fit results from the HCO
3(0,3)-2(0,2) transition to determine the source kinematic properties. We find
\% of the total mass of \emph{CMZoom} sources have reliable
kinematics. Only four compact continuum sources are formally self-gravitating.
The remainder are consistent with being in hydrostatic equilibrium assuming
that they are confined by the high external pressure in the CMZ. Based on the
mass and density of virially bound sources, and assuming star formation occurs
within one free-fall time with a star formation efficiency of , we
place a lower limit on the future embedded star-formation rate of \,M\,yr. We find only two convincing proto-stellar
outflows, ruling out a previously undetected population of very massive,
actively accreting YSOs with strong outflows. Finally, despite having
sufficient sensitivity and resolution to detect high-velocity compact clouds
(HVCCs), which have been claimed as evidence for intermediate mass black holes
interacting with molecular gas clouds, we find no such objects across the large
survey area.Comment: 44 pages, 41 figure
Recommended from our members
Preliminary Assessment of Celecoxib and Microdiode Pulse Laser Treatment of Diabetic Macular Edema
Purpose: Inflammation may play an important role in the pathogenesis of diabetic macular edema, a major cause of vision loss in persons with diabetes. The purpose of this study was to evaluate combined antiinflammatory therapy and laser approaches for treating patients with diabetic macular edema. Methods: In this prospective, factorial, randomized, multicenter trial, we compared cyclo-oxygenase-2 inhibitor (celecoxib) with placebo and diode grid laser with standard Early Treatment Diabetic Retinopathy Study focal laser treatment in 86 participants with diabetic macular edema. The primary outcome is change in visual acuity of ≥15 letters from baseline, and the secondary outcomes include a 50% reduction in the retinal thickening of diabetic macular edema measured by optical coherence tomography and a 50% reduction in leakage severity on fluorescein angiography. Results: Visual acuity and retinal thickening data from >2 years of follow-up did not show evidence of differences between the medical and laser treatments. However, participants assigned to the celecoxib group were more likely to have a reduction in fluorescein leakage when compared with the placebo group (odds ratio = 3.6; P < 0.01). Conclusion: This short-term study did not find large visual function benefits of treatment with celecoxib or diode laser compared with those of standard laser treatment. A suggestive effect of celecoxib in reducing fluorescein leakage was observed
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray
spectrometer, studied since 2015 for flying in the mid-30s on the Athena space
X-ray Observatory, a versatile observatory designed to address the Hot and
Energetic Universe science theme, selected in November 2013 by the Survey
Science Committee. Based on a large format array of Transition Edge Sensors
(TES), it aims to provide spatially resolved X-ray spectroscopy, with a
spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of
5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement
Review (SRR) in June 2022, at about the same time when ESA called for an
overall X-IFU redesign (including the X-IFU cryostat and the cooling chain),
due to an unanticipated cost overrun of Athena. In this paper, after
illustrating the breakthrough capabilities of the X-IFU, we describe the
instrument as presented at its SRR, browsing through all the subsystems and
associated requirements. We then show the instrument budgets, with a particular
emphasis on the anticipated budgets of some of its key performance parameters.
Finally we briefly discuss on the ongoing key technology demonstration
activities, the calibration and the activities foreseen in the X-IFU Instrument
Science Center, and touch on communication and outreach activities, the
consortium organisation, and finally on the life cycle assessment of X-IFU
aiming at minimising the environmental footprint, associated with the
development of the instrument. Thanks to the studies conducted so far on X-IFU,
it is expected that along the design-to-cost exercise requested by ESA, the
X-IFU will maintain flagship capabilities in spatially resolved high resolution
X-ray spectroscopy, enabling most of the original X-IFU related scientific
objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental
Astronomy with minor editin
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory. Athena is a versatile observatory designed to address the Hot and Energetic Universe science theme, as selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), X-IFU aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over a hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR (i.e. in the course of its preliminary definition phase, so-called B1), browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters, such as the instrument efficiency, spectral resolution, energy scale knowledge, count rate capability, non X-ray background and target of opportunity efficiency. Finally, we briefly discuss the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, touch on communication and outreach activities, the consortium organisation and the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with ESA member state contributions from Belgium, Czech Republic, Finland, Germany, Poland, Spain, Switzerland, with additional contributions from the United States and Japan.The French contribution to X-IFU is funded by CNES, CNRS and CEA. This work has been also supported by ASI (Italian Space Agency) through the Contract 2019-27-HH.0, and by the ESA (European Space Agency) Core Technology Program (CTP) Contract No. 4000114932/15/NL/BW and the AREMBES - ESA CTP No.4000116655/16/NL/BW. This publication is part of grant RTI2018-096686-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This publication is part of grant RTI2018-096686-B-C21 and PID2020-115325GB-C31 funded by MCIN/AEI/10.13039/501100011033
Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery
Peer reviewe
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
Instrumentatio
- …