A5057700015- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Medical Imaging Techniques and Applications
- Advanced X-ray Imaging Techniques
- Vehicle emissions and performance
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Radiomics and Machine Learning in Medical Imaging
- Spectroscopy and Laser Applications
- Astrophysical Phenomena and Observations
- Superconducting and THz Device Technology
- Calibration and Measurement Techniques
- Advanced Combustion Engine Technologies
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Atomic and Molecular Physics
- X-ray Diffraction in Crystallography
- High-pressure geophysics and materials
- CCD and CMOS Imaging Sensors
- Laser Design and Applications
University of Connecticut
2017-2024
Center for Astrophysics Harvard & Smithsonian
2014-2024
Harvard University Press
2019
National Radio Astronomy Observatory
2019
University of Alberta
2016
Max Planck Society
2015
Harvard University
2014-2015
Max Planck Institute for Radio Astronomy
2015
Laboratory for Atmospheric and Space Physics
2010-2014
University of Colorado Boulder
2010-2014
We present the first results from science demonstration phase for Hi-GAL survey, <i>Herschel<i/> key program that will map inner Galactic plane of Milky Way in 5 bands. outline our data reduction strategy and some highlights on two observed 2° × tiles approximately centered at <i>l<i/> = 30° 59°. The regions are extremely rich intense highly structured extended emission which shows a widespread organization filaments. Source SEDs can be built hundreds objects fields, physical parameters...
Thermal images of cold dust in the Central Molecular Zone Milky Way, obtained with far-infrared cameras on board Herschel satellite, reveal a ∼3 × 107 M☉ ring dense and clouds orbiting Galactic center. Using simple toy model, an elliptical shape having semi-major axes 100 60 pc is deduced. The major axis this inclined by about 40° respect to plane sky oriented perpendicular Bar. appears trace system stable x2 orbits predicted for barred potential. Sgr A⋆ displaced geometrical center symmetry...
The conversion of gas into stars is a fundamental process in astrophysics and cosmology. Stars are known to form from the gravitational collapse dense clumps interstellar molecular clouds, it has been proposed that resulting star formation rate proportional either amount mass above threshold surface density, or volume density. These star-formation prescriptions appear hold nearby clouds our Milky Way Galaxy's disk as well distant galaxies where rates often much larger. inner 500 pc Galaxy,...
Using spectral-line observations of HNCO, N2H+, and HNC, we investigate the kinematics dense gas in central ~250 pc Galaxy. We present SCOUSE (Semi-automated multi-COmponent Universal Spectral-line fitting Engine), a line algorithm designed to analyse large volumes data efficiently systematically. Unlike techniques which do not account for complex profiles, accurately describes {l, b, v_LSR} distribution CMZ gas, is asymmetric about Sgr A* both position velocity. Velocity dispersions range...
We present the Bolocam Galactic Plane Survey (BGPS), a 1.1 mm continuum survey at 33 effective resolution of 170 square degrees visible from northern hemisphere.The BGPS is one first large area, systematic surveys in millimeter without
We present a catalog of 8358 sources extracted from images produced by the Bolocam Galactic Plane Survey (BGPS). The BGPS is survey millimeter dust continuum emission northern plane. are using custom algorithm, Bolocat, which was designed specifically to identify and characterize objects in large-area maps generated instrument. products facilitate follow-up observations these relatively unstudied objects. 98% complete 0.4 Jy 60 over all object sizes for sensitive (<35). find that can best be...
Context: Despite their profound effect on the universe, formation of massive stars and stellar clusters remains elusive. In past decade, compelling evidence has emerged that suggests Infrared Dark Clouds (IRDCs) may be precursors to clusters. However, usual method for identifying IRDCs is biased by requirement they are seen in absorption against bright mid-IR emission, whereas dust continuum observations allow cold, dense pre-stellar-clusters identified anywhere. Aims: We aim understand what...
The inner few hundred parsecs of the Milky Way harbours gas densities, pressures, velocity dispersions, an interstellar radiation field and a cosmic ray ionisation rate orders magnitude higher than disc; akin to environment found in star-forming galaxies at high-redshift. Previous studies have shown that this region is forming stars per unit mass dense which least order lower disc, potentially violating theoretical predictions. We show all observational star formation diagnostics - both...
Young massive clusters (YMCs) with stellar masses of 104–105 M☉ and core densities stars per cubic pc are thought to be the "missing link" between open extreme extragalactic super star globular clusters. As such, studying initial conditions YMCs offers an opportunity test cluster formation models across full mass range. G0.253 + 0.016 is excellent candidate YMC progenitor. We make use existing multi-wavelength data including recently available far-IR continuum (Herschel/Herschel Infrared...
The Galactic center is the closest region in which we can study star formation under extreme physical conditions like those high-redshift galaxies. We measure temperature of dense gas central molecular zone (CMZ) and examine what drives it. mapped inner 300 pc CMZ temperature-sensitive J = 3-2 para-formaldehyde (p-H$_2$CO) transitions. used $3_{2,1} - 2_{2,0} / 3_{0,3} 2_{0,2}$ line ratio to determine $n \sim 10^4 10^5 $cm$^{-3}$ gas. have produced maps cubes with 30" 1 km/s resolution...
Super star clusters are the end product of formation under most extreme conditions. As such, studying how their final stellar populations assembled from natal progenitor gas clouds can provide strong constraints on theories. An obvious place to look for initial conditions such comparable mass and density, with no activity. We present a method identify demonstrate technique in inner few hundred pc our Galaxy. The highlights three region similar global physical properties previously identified...
We present a re-reduction and expansion of the Bolocam Galactic Plane Survey, first presented by Aguirre et al. (2011) Rosolowsky (2010). The BGPS is 1.1 mm survey dust emission in Northern galactic plane, covering longitudes -10 < \ell 90 latitudes |b| 0.5 with typical 1-\sigma RMS sensitivity 30-100 mJy 33" beam. Version 2 includes an additional 20 square degrees coverage 3rd 4th quadrants 1st quadrant. new data release has improved angular recovery, complete recovery out to 80" partial...
Abstract We report ALMA observations with resolution ≈0.″5 at 3 mm of the extended Sgr B2 cloud in Central Molecular Zone (CMZ). detect 271 compact sources, most which are smaller than 5000 au. By ruling out alternative possibilities, we conclude that these sources consist a mix hypercompact H ii regions and young stellar objects (YSOs). Most newly detected YSOs gas envelopes that, based on their luminosities, must contain masses <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
In this paper we provide a comprehensive description of the internal dynamics G0.253+0.016 (a.k.a. 'the Brick'); one most massive and dense molecular clouds in Galaxy to lack signatures widespread star formation. As potential host future generation high-mass stars, understanding largely quiescent like is critical importance. paper, reanalyse Atacama Large Millimeter Array cycle 0 HNCO $J=4(0,4)-3(0,3)$ data at 3 mm, using two new pieces software which make available community. First,...
The evolution of molecular clouds in galactic centres is thought to differ from that discs due a significant influence the external gravitational potential. We present set numerical simulations orbiting on 100-pc stream Central Molecular Zone (the central $\sim500$ pc Galaxy) and characterise their morphological kinematic response background potential eccentric orbital motion. find are shaped by strong shear torques, tidal geometric deformation, passage through pericentre. Within our...
We use hydrodynamical simulations to study the Milky Way's central molecular zone (CMZ). The include a non-equilibrium chemical network, gas self-gravity, star formation and supernova feedback. resolve structure of interstellar medium at sub-parsec resolution while also capturing interaction between CMZ bar-driven large-scale flow out $R\sim 5\kpc$. Our main findings are as follows: (1) distinction inner ($R\lesssim120$~pc) outer ($120\lesssim R\lesssim450$~pc) that is sometimes proposed in...
Abstract We present Atacama Large Millimeter/submillimeter Array Band 6 (1.3 mm) observations of dense cores in three massive molecular clouds within the central zone (CMZ) Milky Way, including Dust Ridge cloud e, Sgr C, and 20 km s −1 cloud, at a spatial resolution 2000 au. Among 834 identified from 1.3 mm continuum, we constrain temperatures linewidths 253 using local thermodynamic equilibrium methods to fit H 2 CO and/or CH 3 CN spectra. determine their masses dust continuum derived...
The Bolocam Galactic Plane Survey (BGPS) data for a six square degree region of the plane containing center is analyzed and compared to infrared radio continuum data. BGPS 1.1 mm emission consists clumps interconnected by network fainter filaments surrounding cavities, few which are filled with diffuse near-IR indicating presence warm dust or characteristic HII regions supernova remnants. New 350 {\mu}m images environments two brightest regions, Sgr A B, presented. B2 mm-emitting clump in...
Recently, Goodman et al. argued that the very long, thin infrared dark cloud "Nessie" lies directly in Galactic midplane and runs along Scutum–Centaurus Arm position–position–velocity (p–p–v) space as traced by lower-density higher-density gas. Nessie was presented first "bone" of Milky Way, an extraordinarily thin, high-contrast filament can be used to map our Galaxy's "skeleton." Here we present evidence for additional bones arguing is not a curiosity but one several filaments could...
We propose that bound, young massive stellar clusters form from dense clouds have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback of gas ionization is bottled up, enabling star formation to proceed sufficiently high efficiency so resulting cluster remains bound even after removal. estimate observable properties proto-clusters (MPCs) for existing Galactic plane surveys and suggest how they may be sought recent upcoming extragalactic...
The Milky Way's central molecular zone (CMZ) has emerged in recent years as a unique laboratory for the study of star formation. Here we use simulations presented Tress et al. 2020 to investigate formation CMZ. These resolve structure interstellar medium at sub-parsec resolution while also including large-scale flow which CMZ is embedded. Our main findings are follows. (1) While most happens ring $R\gtrsim100 {\, \rm pc}$, significant amount occurs closer SgrA* $R \lesssim 10{\, pc}$. (2)...
The Origins Space Telescope (Origins) traces our cosmic history, from the formation of first galaxies and rise metals to development habitable worlds present-day life. does this through exquisite sensitivity infrared radiation ions, atoms, molecules, dust, water vapor ice, observations extra-solar planetary atmospheres, protoplanetary disks, large-area extragalactic fields. operates in wavelength range 2.8 588 microns is 1000 times more sensitive than its predecessors due large, cold (4.5 K)...
The ALMA-IMF Large Program imaged a total noncontiguous area of 53pc2, covering 15 extreme, nearby protoclusters the Milky Way. They were selected to span relevant early protocluster evolutionary stages. Our 1.3mm and 3mm observations provide continuum images that are homogeneously sensitive point-like cores with masses 0.2 0.6Msun, respectively, matched spatial resolution 2000au. We also detect lines probe structure, kinematics, chemistry, feedback over scales from clouds filaments cores....
The interstellar medium in the Milky Way's Central Molecular Zone (CMZ) is known to be strongly magnetised, but its large-scale morphology and impact on gas dynamics are not well understood. We explore properties of magnetic fields CMZ using three-dimensional non-self gravitating magnetohydrodynamical simulations flow an external Way barred potential. find that: (1) field conveniently decomposed into a regular time-averaged component irregular turbulent component. aligns with velocity...