Pat Roche | Searcharxiv

arXiv2024

Report of the Kavli-IAU Workshop on Global Coordination, "Probing the Universe from far-infrared to millimeter wavelengths: future facilities and their synergies"

This Report summarizes findings and recommendations from the Kavli-IAU workshop on "Probing the Universe from far-infrared to millimeter wavelengths: future facilities and their synergies" which took place from 26 to 28 March 2024 in Pasadena, CA, USA. The workshop aimed to define the needs and potential synergies for different facilities at wavelengths from 30 {\mu}m to a few cm in the post-2030 era, considering both financial and programmatic limitations and exploring how to maximize the scientific insights from the data they will yield in the coming decades. This wavelength range provides unique probes of relatively cool, dense interstellar material central to studying the physics and chemistry of nascent stars, proton-planetary disks, and young forming exoplanets. On larger scales, these facilities probe dust and dense gas in galaxies and around highly obscured accreting supermassive black holes and are thus essential for characterizing feedback processes and galaxy evolution out to the highest redshifts. Solar system and time domain studies are also addressed. The main recommendations include the need for ALMA to develop an ALMA2040 vision; for ngVLA to maintain its momentum and schedule and further develop international partnerships; for far-IR astronomy to pursue a space-based observatory with urgency; and for large aperture, wide field millimeter/submillimeter telescopes to continue studies to mature science and technology.

astro-ph.IM↗

arXiv2019

High angular resolution ALMA images of dust and molecules in the SN 1987A ejecta

We present high angular resolution (~80 mas) ALMA continuum images of the SN 1987A system, together with CO $J$=2 $\!\rightarrow\!$ 1, $J$=6 $\!\rightarrow\!$ 5, and SiO $J$=5 $\!\rightarrow\!$ 4 to $J$=7 $\!\rightarrow\!$ 6 images, which clearly resolve the ejecta (dust continuum and molecules) and ring (synchrotron continuum) components. Dust in the ejecta is asymmetric and clumpy, and overall the dust fills the spatial void seen in H$\alpha$ images, filling that region with material from heavier elements. The dust clumps generally fill the space where CO $J$=6 $\!\rightarrow\!$ 5 is fainter, tentatively indicating that these dust clumps and CO are locationally and chemically linked. In these regions, carbonaceous dust grains might have formed after dissociation of CO. The dust grains would have cooled by radiation, and subsequent collisions of grains with gas would also cool the gas, suppressing the CO $J$=6 $\!\rightarrow\!$ 5 intensity. The data show a dust peak spatially coincident with the molecular hole seen in previous ALMA CO $J$=2 $\!\rightarrow\!$ 1 and SiO $J$=5 $\!\rightarrow\!$ 4 images. That dust peak, combined with CO and SiO line spectra, suggests that the dust and gas could be at higher temperatures than the surrounding material, though higher density cannot be totally excluded. One of the possibilities is that a compact source provides additional heat at that location. Fits to the far-infrared--millimeter spectral energy distribution give ejecta dust temperatures of 18--23K. We revise the ejecta dust mass to $\mathrm{M_{dust}} = 0.2-0.4$M$_\odot$ for carbon or silicate grains, or a maximum of $<0.7$M$_\odot$ for a mixture of grain species, using the predicted nucleosynthesis yields as an upper limit.

astro-ph.HE↗