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We present in this paper mid-infrared (5-8~$\mu$m) spectroscopy toward the massive young binary W3~IRS~5, using the EXES spectrometer in high-resolution mode ($R\sim$50,000) from the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA). Many ($\sim$180) $\nu_2$=1--0 and ($\sim$90) $\nu_2$=2-1 absorption rovibrational transitions are identified. Two hot components over 500 K and one warm component of 190 K are identified through Gaussian fittings and rotation diagram analysis. Each component is linked to a CO component identified in the IRTF/iSHELL observations ($R$=88,100) through their kinematic and temperature characteristics. Revealed by the large scatter in the rotation diagram, opacity effects are important, and we adopt two curve-of-growth analyses, resulting in column densities of $\sim10^{19}$ cm$^{-2}$. In one analysis, the model assumes a foreground slab. The other assumes a circumstellar disk with an outward-decreasing temperature in the vertical direction. The disk model is favored because fewer geometry constraints are needed, although this model faces challenges as the internal heating source is unknown. We discuss the chemical abundances along the line of sight based on the CO-to-H$_2$O connection. In the hot gas, all oxygen not locked in CO resides in water. In the cold gas, we observe a substantial shortfall of oxygen and suggest that the potential carrier could be organics in solid ice., Comment: Accepted for publication in ApJ. 34 pages, 13 figures, and 14 tables. Comments are more than welcome!

Context. Cold cores are one of the first steps of star formation, characterized by densities of a few 104–105 cm−3, low temperatures (15 K and below), and very low external UV radiation. In these dense environments, a rich chemistry takes place on the surfaces of dust grains. Understanding the physico-chemical processes at play in these environments is essential to tracing the origin of molecules that are predominantly formed via reactions on dust grain surfaces. Aims. We observed the cold core LDN 429-C (hereafter L429-C) with the NOEMA interferometer and the IRAM 30 m single dish telescope in order to obtain the gas-phase abundances of key species, including CO and CH3OH. Comparing the data for methanol to the methanol ice abundance previously observed with Spitzer allows us to put quantitative constraints on the efficiency of the non-thermal desorption of this species. Methods. With physical parameters determined from available Herschel data, we computed abundance maps of 11 detected molecules with a non-local thermal equilibrium (LTE) radiative transfer model. These observations allowed us to probe the molecular abundances as a function of density (ranging from a few 103 to a few 106 cm−3) and visual extinction (ranging from 7 to over 75), with the variation in temperature being restrained between 12 and 18 K. We then compared the observed abundances to the predictions of the Nautilus astrochemical model. Results. We find that all molecules have lower abundances at high densities and visual extinctions with respect to lower density regions, except for methanol, whose abundance remains around 4.5 × 10−10 with respect to H2. The CO abundance spreads over a factor of 10 (from an abundance of 10−4 with respect to H2 at low density to 1.8 × 10−5 at high density) while the CS, SO, and H2S abundances vary by several orders of magnitude. No conclusion can be drawn for CCS, HC3N, and CN because of the lack of detections at low densities. Comparing these observations with a grid of chemical models based on the local physical conditions, we were able to reproduce these observations, allowing only the parameter time to vary. Higher density regions require shorter times than lower density regions. This result can provide insights on the timescale of the dynamical evolution of this region. The increase in density up to a few 104 cm−3 may have taken approximately 105 yr, while the increase to 106 cm−3 occurs over a much shorter time span (104 yr). Comparing the observed gas-phase abundance of methanol with previous measurements of the methanol ice, we estimate a non-thermal desorption efficiency between 0.002 and 0.09%, increasing with density. The apparent increase in the desorption efficiency cannot be reproduced by our model unless the yield of cosmic-ray sputtering is altered due to the ice composition varying as a function of density.

Icy grain mantles are the main reservoir of the volatile elements that link chemical processes in dark, interstellar clouds with the formation of planets and composition of their atmospheres. The initial ice composition is set in the cold, dense parts of molecular clouds, prior to the onset of star formation. With the exquisite sensitivity of JWST, this critical stage of ice evolution is now accessible for detailed study. Here we show the first results of the Early Release Science program "Ice Age" that reveal the rich composition of these dense cloud ices. Weak ices, including, $^{13}$CO$_2$, OCN$^-$, $^{13}$CO, OCS, and COMs functional groups are now detected along two pre-stellar lines of sight. The $^{12}$CO$_2$ ice profile indicates modest growth of the icy grains. Column densities of the major and minor ice species indicate that ices contribute between 2 and 19% of the bulk budgets of the key C, O, N, and S elements. Our results suggest that the formation of simple and complex molecules could begin early in a water-ice rich environment., Comment: To appear in Nature Astronomy on January 23rd, 2023. 33 pages, 16 figures, 3 tables; includes extended and supplemental data sections. Part of the JWST Ice Age Early Release Science program's science enabling products. Enhanced spectra downloadable on Zenodo at the following DOI: 10.5281/zenodo.7501239

The properties of dust change during the transition from diffuse to dense clouds as a result of ice formation and dust coagulation, but much is still unclear about this transformation. We present 2-20 micron spectra of 49 field stars behind the Perseus and Serpens Molecular Clouds and establish relationships between the near-infrared continuum extinction (AK) and the depths of the 9.7 micron silicate (tau97) and 3.0 micron H2O ice (tau30) absorption bands. The tau97/AK ratio varies from large, diffuse interstellar medium-like values (~0.55), to much lower ratios (~0.26). Above extinctions of AK~1.2 (AV~10; Perseus, Lupus, dense cores) and ~2.0 (AV~17; Serpens), the tau97/AK ratio is lowest. The tau97/AK reduction from diffuse to dense clouds is consistent with a moderate degree of grain growth (sizes up to ~0.5 micron), increasing the near-infrared color excess (and thus AK), but not affecting ice and silicate band profiles. This grain growth process seems to be related to the ice column densities and dense core formation thresholds, highlighting the importance of density. After correction for Serpens foreground extinction, the H2O ice formation threshold is in the range of AK=0.31-0.40 (AV=2.6-3.4) for all clouds, and thus grain growth takes place after the ices are formed. Finally, abundant CH3OH ice (~21% relative to H2O) is reported for 2MASSJ18285266+0028242 (Serpens), a factor of >4 larger than for the other targets., 29 pages+17 pages appendix. Published in The Astrophysical Journal, 930, 2, 2022

Acknowledgments We thank the participants of the FPF meetings and the Snowmass working groups for discussions that have contributed both directly and indirectly to this study. We gratefully acknowledge the invaluable support of the CERN Physics Beyond Colliders study group and the work of CERN technical teams related to civil engineering studies (SCE-DOD), safety discussions (HSE-OHS, HSE-RP, EP-DI-SO), integration (EN-ACE), and discussions on services (EN-CV, EN-EL, EN-AA) and simulations (SY-STI). The work by J Alameddine, W Rhode, T Ruhe, and A Sandrock has been supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Collaborative Research Center SFB 876 and SFB 1491. L A Anchordoqui is supported by the US National Science Foundation (NSF) Grant PHY-2112527. T Araki is supported by JP18H01210. A Ariga is supported by JSPS KAKENHI Grant JP20K23373 and the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (Grant 101002690). T Ariga acknowledges support from JSPS KAKENHI Grant JP19H01909. K Asai is supported by JSPS KAKENHI Grant JP19J13812 and JP21K20365. A Bacchetta and F G Celiberto acknowledge support from the INFN/NINPHA project. P Bakhti and M Rajaee are supported by the National Research Foundation of Korea (NRF-2020R1I1A3072747). B Barman received funding from the Patrimonio Autónomo—Fondo Nacional de Financiamiento para la Ciencia, la Tecnología y la Innovación Francisco José de Caldas (MinCiencias—Colombia) Grant 80740-465-2020 and the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No. 860881-HIDDeN. The work of B Batell is supported by the US Department of Energy (DOE) Grant DE–SC0007914. The work of A Berlin, T J Hobbs, S Hoeche, and J G Morfín was supported by the Fermi National Accelerator Laboratory (Fermilab), a US DOE, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract DE-AC02-07CH11359. M Becker, E Copello and J Harz acknowledge support from the DFG Emmy Noether Grant HA 8555/1-1. E Copello acknowledges also support from the DFG Collaborative Research Centre 'Neutrinos and Dark Matter in Astro- and Particle Physics' (SFB 1258). E Bertuzzo acknowledges financial support from FAPESP Contracts 2015/25884-4 and 2019/15149-6 and is indebted to the Theoretical Particle Physics and Cosmology group at King's College London for hospitality. The work of J Bian and W Wu is supported in part by US DOE Grant DE-SC0009920 and Heising-Simons Foundation Grant 2022-3319. The work of A Boyarsky and M Ovchynnikov is supported by the ERC under the European Union's Horizon 2020 Research and Innovation Programme (GA 694896). A Carmona acknowledges funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Grant Agreement No. 754446 and UGR Research and Knowledge Transfer Found—Athenea3i. A Carmona also acknowledges partial support by the Ministry of Science and Innovation and SRA (10.13039/501100011033) Grant PID2019-106087GB-C22 and by the Junta de Andalucía Grant A-FQM-472-UGR20. F G Celiberto thanks the Università degli Studi di Pavia for the warm hospitality. The work of G Chachamis was supported by the Fundação para a Ciência e a Tecnologia (Portugal) under Project CERN/FIS-PAR/0024/2019 and Contract 'Investigador auxiliar FCT—Individual Call/03216/2017'. The work of M Citron and D Stuart is supported by US DOE Grant DE-SC0011702. The work of L Darme is supported by the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement 101028626. P B Denton acknowledges support from the US DOE Grant Contract DE-SC0012704. The work of P S Bhupal Dev was supported in part by the US DOE Grant DE-SC0017987. The research activities of K R Dienes were supported in part by the US DOE Grant DE-FG02-13ER41976/DE-SC0009913 and also by the US NSF through its employee IR/D program. M V Diwan acknowledges support from the US DOE Grant Contract DE-SC0012704. Y Du and J H Yu are supported in part by National Key Research and Development Program of China Grant 2020YFC2201501, and the National Science Foundation of China (NSFC) under Grants 12022514, 11875003 and 12047503, and CAS Project for Young Scientists in Basic Research YSBR-006, and the Key Research Program of the CAS Grant XDPB15. The work of B Dutta and S Ghosh are supported in part by the US DOE Grant DE-SC0010813. The work of S Ghosh is also supported in part by National Research Foundation of Korea (NRF)'s Grants, Grant 6N021413. Y Farzan has received financial support from Saramadan Contract ISEF/M/400279 as well as from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Grant Agreement 860881-HIDDeN. The work of J L Feng is supported in part by US NSF Grants PHY-1915005 and PHY-2111427, Simons Investigator Award #376204, Simons Foundation Grant 623683, and Heising-Simons Foundation Grants 2019-1179 and 2020-1840. M Fieg is supported in part by US NSF Grant PHY-1915005 and by NSF Graduate Research Fellowship Award DGE-1839285. A L Foguel is supported by FAPESP Contract 2020/00174-2. The work of P Foldenauer is supported by the UKRI Future Leaders Fellowship DARKMAP. The work of S Foroughi-Abari and A Ritz is supported in part by NSERC, Canada. The work of J-F Fortin is supported in part by NSERC, Canada. A Friedland is supported by the US DOE Grant DE-AC02-76SF00515. E Fuchs acknowledges support by the DFG Germany's Excellence Strategy—EXC-2123 'QuantumFrontiers'—390837967. M Fucilla, M M A Mohammed, and A Papa acknowledge support from the INFN/QFT@COLLIDERS project. A Garcia acknowledges support from the European Union's H2020-MSCA Grant Agreement 101025085. C A García Canal and S J Sciutto acknowledge support from CONICET and ANPCyT M V Garzelli acknowledges support the from German BMBF Contract 05H21GUCCA. V P Goncalves was partially financed by the Brazilian funding agencies CNPq, CAPES, FAPERGS and INCT-FNA (Process Number 464898/2014-5). S Goswami acknowledges the J C Bose Fellowship (JCB/2020/000011) of Science and Engineering Research Board of Department of Science and Technology, Government of India. The work of M Guzzi is supported by US NSF Grant PHY-2112025. L Harland-Lang thanks the Science and Technology Facilities Council (STFC) for support via Grant Award ST/L000377/1. The work of S P Harris is supported by the US DOE Grant DE-FG02-00ER41132 as well as the US NSF Grant PHY-1430152 (JINA Center for the Evolution of the Elements). J C Helo acknowledge support from Grant ANID FONDECYT-Chile 1201673 and ANID—Millennium Science Initiative Program ICN2019-044. The work of M Hirsch is supported by the Spanish Grants PID2020-113775GB-I00 (AEI/10.13039/501100011033) and PROMETEO/2018/165 (Generalitat Valenciana). The work of A Hryczuk and M Laletin is supported by the National Science Centre, Poland, research Grant 2018/31/D/ST2/00813. The research activities of F Huang are supported by the International Postdoctoral Exchange Fellowship Program and in part by US NSF Grant PHY-1915005. A Ismail is supported by NSERC (Reference Number 557763) and by US NSF Grant PHY-2014071. Y S Jeong acknowledges support from the National Research Foundation of Korea (NRF) grant funded by the Korea government through Ministry of Science and ICT Grant 2021R1A2C1009296. K Jodlowski and L Roszkowski are supported by the National Science Centre, Poland, research Grant 2015/18/A/ST2/00748. S R Klein is supported in part by the US NSF Grant PHY-1307472 and the US DOE Contract DE-AC-76SF00098. F Kling and P Quílez are supported by the DFG under Germany's Excellence Strategy—EXC 2121 Quantum Universe—390833306. P Ko is supported in part by KIAS Individual Grant PG021403 and by National Research Foundation of Korea (NRF) Grant NRF-2019R1A2C3005009. S Kulkarni is supported by the Austrian Science Fund Elise-Richter Grant V592-N27. The work of J Kumar is supported in part by US DOE Grant DE-SC0010504. J-L Kuo is supported by US NSF Theoretical Physics Program, Grant PHY-1915005. The work of C Le Roux and K Zapp is part of a project that has received funding from the ERC under the European Union's Horizon 2020 Research and Innovation Programme (Grant Agreement 803183, collectiveQCD). The work of H-S Lee was supported in part by the National Research Foundation of Korea (NRF-2021R1A2C2009718). S J Lee was supported by the Samsung Science and Technology Foundation. Ji Li is supported by the National Natural Science Foundation of China Grant 11905149. K-F Lyu and Z Liu are supported in part by the US DOE Grant DE-SC0022345. The work of R Maciula and A Szczurek was partially supported by the Polish National Science Centre under Grant 2018/31/B/ST2/03537. R Mammen Abraham and A Ismail acknowledge support from the US DOE Grant DE-SC0016013. M R Masouminia is supported by the UK Science and Technology Facilities Council (Grant ST/P001246/1). The work of J McFayden was supported by the Royal Society Fellowship Grant URF R1 201519. The work of O Mikulenko is supported by the NWO Physics Vrij Programme 'The Hidden Universe of Weakly Inter-acting Particles' with Project Number 680.92.18.03 (NWO Vrije Programma), which is (partly) financed by the Dutch Research Council (NWO). P Nadolsky and F Olness acknowledge support through US DOE Grant DE-SC0010129. E R Nocera thanks the STFC for support by the Grant Awards ST/P000630/1and ST/T000600/1. The work of N Okada is supported by the US DOE Grant DE-SC0012447. V Pandey acknowledges the support from US DOE Grant DE-SC0009824. The work of D Raut is supported by the US DOE Grant DE-SC0013880. P Reimitz acknowledges financial support from FAPESP Contract 2020/10004-7. M H Reno is supported in part by US DOE Grant DE-SC-0010113. The work of J Rojo is partly supported by the Dutch Research Council (NWO). L Roszkowski and S Trojanowski are supported by the grant 'AstroCeNT: Particle Astrophysics Science and Technology Centre' carried out within the International Research Agendas programme of the Foundation for Polish Science financed by the European Union under the European Regional Development Fund. S Trojanowski is also supported in part by the Polish Ministry of Science and Higher Education through its scholarship for young and outstanding scientists (Decision No. 1190/E-78/STYP/14/2019). S Trojanowski is also supported in part from the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement No. 952480 (DarkWave 24 project). I Sarcevic is supported by US DOE Grant DOE DE-SC-0009913. The work of L Shchutska is supported by the ERC under the European Union's Horizon 2020 Research and Innovation Programme (GA 758316). The work of T Shimomura is supported by JSPS KAKENHI Grants JP18H01210, JP18K03651, and MEXT KAKENHI Grant JP18H05543. The work of K Sinha is supported in part by US DOE Grant DE-SC0009956. The work of T Sjöstrand is supported by the Swedish Research Council, Contract 2016-05996. J T Sobczyk acknowledges support from NCN Grant UMO-2021/41/B/ST2/02778. D Soldin acknowledges support from the US NSF Grant PHY-1913607. H Song is supported by the International Postdoctoral Exchange Fellowship Program. Y Soreq is supported by grants from the NSF-BSF, BSF, the ISF and by the Azrieli foundation. A Stasto acknowledges support from US DOE Grant DE-SC-0002145. S Su is supported by the US DOE Grant DE-FG02-13ER41976/DE-SC0009913. W Su is supported by a KIAS Individual Grant (PG084201) at Korea Institute for Advanced Study. Y Takubo is supported by JP20K04004. M Taoso acknowledges support from the INFN Grant 'LINDARK', the research grant 'The Dark Universe: A Synergic Multimessenger Approach 2017X7X85' funded by MIUR, and the project 'Theoretical Astroparticle Physics (TAsP)' funded by the INFN. The research activities of B Thomas are supported in part by US NSF Grant PHY-2014104. The work of Y-D Tsai is supported in part by US NSF Grant PHY-1915005. The work of A Sabio Vera has been supported by the Spanish Research Agency (Agencia Estatal de Investigación) through the Grant IFT Centro de Excelencia Severo Ochoa SEV-2016-0597, by the Spanish Government Grant FPA2016-78022-P and from the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement 824093. The work of Yongchao Zhang is supported by the National Natural Science Foundation of China Grant 12175039, the 2021 Jiangsu Shuangchuang (Mass Innovation and Entrepreneurship) Talent Program JSSCBS20210144, and the 'Fundamental Research Funds for the Central Universities'. Yue Zhang is supported by the Arthur B McDonald Canadian Astroparticle Physics Research Institute. R Zukanovich Funchal is partially supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Ciência e Tecnologia (CNPq). The opinions and conclusions expressed herein are those of the authors and do not represent any funding agencies., High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential., German Research Foundation (DFG) SFB 876 SFB 1491, National Science Foundation (NSF) PHY2112527, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (KAKENHI) JP18H01210 JSPS KAKENHI JP20K23373 JP19H01909 JSPS KAKENHI JP19J13812 JP21K20365 JSPS KAKENHI JP18K03651, European Research Council (ERC) 101002690, National Research Foundation of Korea NRF-2020R1I1A3072747, Patrimonio Autónomo-Fondo Nacional de Financiamiento para la Ciencia Tecnología y la Innovación Francisco José de Caldas (MinCiencias-Colombia) 80740-465-2020, European Commission Joint Research Centre 860881-HIDDeN European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant 754446, United States Department of Energy (DOE) DE-SC0007914, Fermi National Accelerator Laboratory (Fermilab), a US DOE, Office of Science, HEP User Facility, Fermi Research Alliance, LLC (FRA) DE-AC02-07CH11359, German Research Foundation (DFG) HA 8555/1-1, DFG Collaborative Research Centre 'Neutrinos and Dark Matter in Astro-and Particle Physics' SFB 1258, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2015/25884-4 2019/15149-6, United States Department of Energy (DOE) DE-SC0009920, Heising-Simons Foundation 2022-3319 2019-1179 2020-1840, ERC under the European Union's Horizon 2020 Research and Innovation Programme 694896 803183, UGR Research and Knowledge Transfer Found-Athenea3i, Ministry of Science and Innovation, Spain (MICINN) Spanish Government, SRA Grant PID2019-106087GB-C22, Junta de Andalucía A-FQM-472-UGR20, Fundacao para a Ciencia e a Tecnologia (FCT) CERN/FIS-PAR/0024/2019 03216/2017, United States Department of Energy (DOE) DE-SC0011702 DE-SC0017987 DE-FG02-13ER41976/DE-SC0009913 DE-SC0012704 DE-SC0010813 DE-AC02-76SF00515 DE-FG02-00ER41132 DE-AC-76SF00098 DE-SC0010504 DE-SC0022345 DE-SC0010129, US NSF through its employee IR/D program, National Key Research and Development Program of China 2020YFC2201501, National Natural Science Foundation of China (NSFC) 12022514 11875003 12047503, CAS Project for Young Scientists in Basic Research YSBR-006, Key Research Program of the CAS XDPB15, National Research Foundation of Korea (NRF)'s Grants 6N021413, Saramadan Contract ISEF/M/400279, National Science Foundation (NSF) PHY-1915005 PHY-2111427 PHY1430152 PHY-2014071 PHY-1307472 PHY-2014104, Simons Investigator Award 376204, Simons Foundation 623683, National Science Foundation (NSF) DGE-1839285, FAPESP Contract 2020/00174-2, UKRI Future Leaders Fellowship DARKMAP, Natural Sciences and Engineering Research Council of Canada (NSERC), German Research Foundation (DFG) EXC-2123 390837967, INFN/QFT@COLLIDERS project, European Union's H2020-MSCA Grant Agreement 101025085, Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), ANPCyT, Federal Ministry of Education & Research (BMBF) 05H21GUCCA, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ), Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), Fundacao de Amparo a Ciencia e Tecnologia do Estado do Rio Grande do Sul (FAPERGS), INCT-FNA 464898/2014-5, J C Bose Fellowship of Science and Engineering Research Board of Department of Science and Technology, Government of India JCB/2020/000011, National Science Foundation (NSF) PHY-2112025, UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC) Science and Technology Development Fund (STDF) ST/L000377/1, Grant ANID FONDECYT-Chile 1201673, ANID-Millennium Science Initiative Program ICN2019-044, Spanish Grant (AEI) PID2020-113775GBI00, Center for Forestry Research & Experimentation (CIEF) PROMETEO/2018/165, National Science Centre, Poland 2018/31/D/ST2/00813, International Postdoctoral Exchange Fellowship Program, KIAS Individual Grant PG021403, National Research Foundation of Korea NRF-2019R1A2C3005009, Austrian Science Fund Elise-Richter Grant V592-N27, US NSF Theoretical Physics Program PHY-1915005, Samsung, National Natural Science Foundation of China (NSFC) 11905149, Polish National Science Centre 2018/31/B/ST2/03537, UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC) ST/P001246/1, Royal Society of London URF R1 201519, Netherlands Organization for Scientific Research (NWO) 680.92.18.03 Physics Vrij Programme .The Hidden Universe of Weakly Inter-acting Particles' - Dutch Research Council (NWO), UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC) ST/T000600/1 ST/P000630/1, Netherlands Organization for Scientific Research (NWO), European Union under the European Regional Development Fund, Polish Ministry of Science and Higher Education through its scholarship for young and outstanding scientists 1190/E-78/STYP/14/2019, European Commission 952480, ERC under the European Union 758316, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) JP18H05543 MEXT KAKENHI, Swedish Research Council 2016-05996, NCN UMO-2021/41/B/ST2/02778, NSF-BSF, US-Israel Binational Science Foundation, Israel Science Foundation, Azrieli foundation, KIAS Individual Grant at Korea Institute for Advanced Study PG084201, Istituto Nazionale di Fisica Nucleare (INFN), Ministry of Education, Universities and Research (MIUR) 2017X7X85', Spanish Government SEV-2016-0597 Spanish Research Agency (Agencia Estatal de Investigacion) through the Grant IFT Centro de Excelencia Severo Ochoa FPA2016-78022-P, European Union's Horizon 2020 Research and Innovation Programme 824093, National Natural Science Foundation of China (NSFC) 12175039, 2021 Jiangsu Shuangchuang (Mass Innovation and Entrepreneurship) Talent Program JSSCBS20210144, Fundamental Research Funds for the Central Universities, Arthur B McDonald Canadian Astroparticle Physics Research Institute, Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), United States Department of Energy (DOE) DE-SC0012447 DE-SC0009824 DE-SC0013880 :The US DOE DE-SC-0010113 DOE DE-SC-0009913 US DOE DE-SC0009956 DE-FG02-13ER41976/DESC0009913 US DOE JP20K04004

Funder: ZNS - Hannelore Kohl Stiftung; funder-id: http://dx.doi.org/10.13039/501100007731, Funder: OneMind (USA), Funder: Integra LifeSciences; funder-id: http://dx.doi.org/10.13039/100009006, Background: Traumatic brain injury (TBI) is an important global public health burden, where those injured by high-energy transfer (e.g., road traffic collisions) are assumed to have more severe injury and are prioritised by emergency medical service trauma triage tools. However recent studies suggest an increasing TBI disease burden in older people injured through low-energy falls. We aimed to assess the prevalence of low-energy falls among patients presenting to hospital with TBI, and to compare their characteristics, care pathways, and outcomes to TBI caused by high-energy trauma. Methods and findings: We conducted a comparative cohort study utilising the CENTER-TBI (Collaborative European NeuroTrauma Effectiveness Research in TBI) Registry, which recorded patient demographics, injury, care pathway, and acute care outcome data in 56 acute trauma receiving hospitals across 18 countries (17 countries in Europe and Israel). Patients presenting with TBI and indications for computed tomography (CT) brain scan between 2014 to 2018 were purposively sampled. The main study outcomes were (i) the prevalence of low-energy falls causing TBI within the overall cohort and (ii) comparisons of TBI patients injured by low-energy falls to TBI patients injured by high-energy transfer—in terms of demographic and injury characteristics, care pathways, and hospital mortality. In total, 22,782 eligible patients were enrolled, and study outcomes were analysed for 21,681 TBI patients with known injury mechanism; 40% (95% CI 39% to 41%) (8,622/21,681) of patients with TBI were injured by low-energy falls. Compared to 13,059 patients injured by high-energy transfer (HE cohort), the those injured through low-energy falls (LE cohort) were older (LE cohort, median 74 [IQR 56 to 84] years, versus HE cohort, median 42 [IQR 25 to 60] years; p < 0.001), more often female (LE cohort, 50% [95% CI 48% to 51%], versus HE cohort, 32% [95% CI 31% to 34%]; p < 0.001), more frequently taking pre-injury anticoagulants or/and platelet aggregation inhibitors (LE cohort, 44% [95% CI 42% to 45%], versus HE cohort, 13% [95% CI 11% to 14%]; p < 0.001), and less often presenting with moderately or severely impaired conscious level (LE cohort, 7.8% [95% CI 5.6% to 9.8%], versus HE cohort, 10% [95% CI 8.7% to 12%]; p < 0.001), but had similar in-hospital mortality (LE cohort, 6.3% [95% CI 4.2% to 8.3%], versus HE cohort, 7.0% [95% CI 5.3% to 8.6%]; p = 0.83). The CT brain scan traumatic abnormality rate was 3% lower in the LE cohort (LE cohort, 29% [95% CI 27% to 31%], versus HE cohort, 32% [95% CI 31% to 34%]; p < 0.001); individuals in the LE cohort were 50% less likely to receive critical care (LE cohort, 12% [95% CI 9.5% to 13%], versus HE cohort, 24% [95% CI 23% to 26%]; p < 0.001) or emergency interventions (LE cohort, 7.5% [95% CI 5.4% to 9.5%], versus HE cohort, 13% [95% CI 12% to 15%]; p < 0.001) than patients injured by high-energy transfer. The purposive sampling strategy and censorship of patient outcomes beyond hospital discharge are the main study limitations. Conclusions: We observed that patients sustaining TBI from low-energy falls are an important component of the TBI disease burden and a distinct demographic cohort; further, our findings suggest that energy transfer may not predict intracranial injury or acute care mortality in patients with TBI presenting to hospital. This suggests that factors beyond energy transfer level may be more relevant to prehospital and emergency department TBI triage in older people. A specific focus to improve prevention and care for patients sustaining TBI from low-energy falls is required.

To study the demographics of interstellar ices in the Central Molecular Zone (CMZ) of the Milky Way, we obtain near-infrared spectra of $109$ red point sources using NASA IRTF/SpeX at Maunakea. We select the sample from near- and mid-infrared photometry, including $12$ objects in the previous paper of this series, to ensure that these sources trace a large amount of absorption through clouds in each line of sight. We find that most of the sample ($100$ objects) show CO band-head absorption at $2.3\ μ$m, tagging them as red (super-) giants. Despite the photospheric signature, however, a fraction of the sample with $L$-band spectra ($9/82=0.11$) exhibit large H$_2$O ice column densities ($N > 2\times10^{18}\ {\rm cm}^{-2}$), and six of them also reveal CH$_3$OH ice absorption. As one of such objects is identified as a young stellar object (YSO) in our previous work, these ice-rich sight lines are likely associated with background stars in projection to an extended envelope of a YSO or a dense cloud core. The low frequency of such objects in the early stage of stellar evolution implies a low star-formation rate ($, 28 pages, 12 figures, 3 tables. Accepted for publication in the Astrophysical Journal

An important tracer of the origin and evolution of cometary ices is the comparison with ices found in dense clouds and towards Young Stellar Objects (YSOs). We present a survey of ices in the 2-5 micron spectra of 23 massive YSOs, taken with the NASA InfraRed Telescope Facility SpeX spectrometer. The 4.90 micron absorption band of OCS ice is detected in 20 sight-lines, more than five times the previously known detections. The absorption profile shows little variation and is consistent with OCS being embedded in CH3OH-rich ices, or proton-irradiated H$_2$S or SO$_2$-containing ices. The OCS column densities correlate well with those of CH$_3$OH and OCN$^-$, but not with H$_2$O and apolar CO ice. This association of OCS with CH$_3$OH and OCN$^-$ firmly establishes their formation location deep inside dense clouds or protostellar envelopes. The median composition of this ice phase towards massive YSOs, as a percentage of H$_2$O, is CO:CH$_3$OH:OCN$^-$:OCS=24:20:1.53:0.15. CS, due to its low abundance, is likely not the main precursor to OCS. Sulfurization of CO is likely needed, although the source of this sulfur is not well constrained. Compared to massive YSOs, low mass YSOs and dense clouds have similar CO and CH$_3$OH ice abundances, but less OCN$^-$ and more apolar CO, while OCS awaits detection. Comets tend to be under-abundant in carbon-bearing species, but this does not appear to be the case for OCS, perhaps signalling OCS production in protoplanetary disks., Comment: 35 pages, 18 figures. Published ApJ 941, 32. Updated arXiv title and publication information

This work presents ground-based spectrally-resolved water emission at R = 30000-100000 over infrared wavelengths covered by JWST (2.9-12.8 $\mu$m). Two new surveys with iSHELL and VISIR are combined with previous spectra from CRIRES and TEXES to cover parts of multiple ro-vibrational and rotational bands observable within telluric transmission bands, for a total of $\approx160$ spectra and 85 disks (30 of which are JWST targets in Cycle 1). The general expectation of a range of regions and excitation conditions traced by infrared water spectra is for the first time supported by the combined kinematics and excitation as spectrally resolved at multiple wavelengths. The main findings from this analysis are: 1) water lines are progressively narrower from the ro-vibrational bands at 2-9 $\mu$m to the rotational lines at 12 $\mu$m, and partly match a broad (BC) and narrow (NC) emission components, respectively, as extracted from ro-vibrational CO spectra; 2) rotation diagrams of resolved water lines from upper level energies of 4000-9500 K show vertical spread and curvatures indicative of optically thick emission ($\approx 10^{18}$ cm$^{-2}$) from a range of excitation temperatures ($\approx 800$-1100 K); 3) the new 5 $\mu$m spectra demonstrate that slab model fits to the rotational lines at $> 10$ $\mu$m strongly over-predict the ro-vibrational emission bands at $< 9$ $\mu$m, implying non-LTE vibrational excitation. We discuss these findings in the context of emission from a disk surface and a molecular inner disk wind, and provide a list of guidelines to support the analysis of spectrally-unresolved JWST spectra., Comment: Accepted for publication on AJ

We present in this paper the results of high spectral resolution ($R$=88,100) spectroscopy at 4.7 $\mu$m with iSHELL/IRTF of hot molecular gas close to the massive binary protostar W3 IRS5. The binary was spatially resolved and the spectra of the two sources (MIR1 and MIR2) were obtained simultaneously for the first time. Hundreds of $^{12}$CO $\nu$=0-1, $\nu$=1-2 lines, and $\nu$=0-1 transitions of the isotopes of $^{12}$CO were detected in absorption, and are blue-shifted compared to the cloud velocity $v_{LSR}=-$38 km/s. We decompose and identify kinematic components from the velocity profiles, and apply rotation diagram and curve of growth analyses to determine their physical properties. Temperatures and column densities of the identified components range from 30$-$700 K and 10$^{21}-$10$^{22}$ cm$^{-2}$, respectively. Our curve of growth analyses consider two scenarios. One assumes a foreground slab with a partial covering factor, which well reproduces the absorption of most of the components. The other assumes a circumstellar disk with an outward decreasing temperature in the vertical direction, and reproduces the absorption of all the hot components. We attribute the physical origins of the identified components to the foreground envelope ($, Comment: Accepted for publication in ApJ. 26 pages, 12 figures, and 9 tables. Comments are more than welcome!

We present an overview and first results from a $M$-band spectroscopic survey of planet-forming disks performed with iSHELL on IRTF, using two slits that provide resolving power R $\approx$ 60,000-92,000 (5-3.3 km/s). iSHELL provides a nearly complete coverage at 4.52-5.24 $μ$m in one shot, covering $>50$ lines from the R and P branches of $^{12}$CO and $^{13}$CO for each of multiple vibrational levels, and providing unprecedented information on the excitation of multiple emission and absorption components. Some of the most notable new findings of this survey are: 1) the detection of two CO Keplerian rings at $, Accepted for publication on The Astronomical Journal

CO is one of the most abundant ice components on interstellar dust grains. When it is mixed with amorphous solid water (ASW) or located on its surface, an absorption band of CO at 2152 cm$^{-1}$ is always present in laboratory measurements. This spectral feature is attributed to the interaction of CO with dangling-OH bonds (dOH) in ASW. However, this band is absent in observational spectra of interstellar ices. This raises the question whether CO forms a relatively pure layer on top of ASW or is in close contact with ASW, but not via dangling bonds. We aim to determine whether the incorporation of NH$_3$ or CO$_2$ into ASW blocks the dOH and therefore reduces the 2152 cm$^{-1}$ band. We performed laboratory experiments to simulate the layered structure of the ice mantle, that is, we grew CO ice on top of 1) pure ASW, 2) NH$_3$:H$_2$O=10:100 mixed ice, and 3) CO$_2$:H$_2$O=20:100 mixed ice. Infrared spectra were measured to quantify the strength of the 2152 cm$^{-1}$ band. In addition, a second set of experiments were performed to determine how the incorporation of NH$_3$ into ASW affects the dOH band. We found that annealing the ice reduces the 2152 cm$^{-1}$ band and that NH$_3$ blocks the dOH on ASW surface and therefore reduces the 2152 cm$^{-1}$ band more effectively than CO$_2$. We suggest that this difference between NH$_3$ and CO$_2$ can be ascribed to the polarity of the guest molecule (NH$_3$ is a polar species, whereas CO$_2$ is apolar). The polarity implies that the formation of an H-bond between the N atom of ammonia and the dOH is a barrier-less reaction. We also determined the pore surface area of the ice mixtures as a function of the annealing temperature, and found that the nondetection of 2152 cm$^{-1}$ band does not necessarily exclude the possibility of a porous ice mantle., Comment: 10 pages, 10 figures

The chemical inventory of planets is determined by the physical and chemical processes that govern the early phases of star formation. The aim is to investigate N-bearing complex organic molecules towards two Class 0 protostars (B1-c and S68N) at millimetre wavelengths with ALMA. Next, the results of the detected N-bearing species are compared with those of O-bearing species for the same and other sources. ALMA observations in Band 6 ($\sim$ 1 mm) and Band 5 ($\sim$ 2 mm) are studied at $\sim$ 0.5" resolution, complemented by Band 3 ($\sim$ 3 mm) data in a $\sim$ 2.5" beam. NH2CHO, C2H5CN, HNCO, HN13CO, DNCO, CH3CN, CH2DCN, and CHD2CN are identified towards the investigated sources. Their abundances relative to CH3OH and HNCO are similar for the two sources, with column densities that are typically an order of magnitude lower than those of O-bearing species. The largest variations, of an order of magnitude, are seen for NH2CHO abundance ratios with respect to HNCO and CH3OH and do not correlate with the protostellar luminosity. In addition, within uncertainties, the N-bearing species have similar excitation temperatures to those of O-bearing species ($\sim$ 100 $\sim$ 300 K). The similarity of most abundances with respect to HNCO, including those of CH2DCN and CHD2CN, hints at a shared chemical history, especially the high D/H ratio in cold regions prior to star formation. However, some of the variations in abundances may reflect the sensitivity of the chemistry to local conditions such as temperature (e.g. NH2CHO), while others may arise from differences in the emitting areas of the molecules linked to their different binding energies in the ice. The two sources discussed here add to the small number of sources with such a detailed chemical analysis on Solar System scales. Future JWST data will allow a direct comparison between the ice and gas abundances of N-bearing species., Accepted to A&A, 41 pages, 37 figures

Chemical models and experiments indicate that interstellar dust grains and their ice mantles play an important role in the production of complex organic molecules (COMs). To date, the most complex solid-phase molecule detected with certainty in the ISM is methanol, but the James Webb Space Telescope (JWST) may be able to identify still larger organic species. In this study, we use a coupled chemo-dynamical model to predict new candidate species for JWST detection toward the young star-forming core Cha-MMS1, combining the gas-grain chemical kinetic code MAGICKAL with a 1-D radiative hydrodynamics simulation using Athena++. With this model, the relative abundances of the main ice constituents with respect to water toward the core center match well with typical observational values, providing a firm basis to explore the ice chemistry. Six oxygen-bearing COMs (ethanol, dimethyl ether, acetaldehyde, methyl formate, methoxy methanol, and acetic acid), as well as formic acid, show abundances as high as, or exceeding, 0.01% with respect to water ice. Based on the modeled ice composition, the infrared spectrum is synthesized to diagnose the detectability of the new ice species. The contribution of COMs to IR absorption bands is minor compared to the main ice constituents, and the identification of COM ice toward the core center of Cha-MMS1 with the JWST NIRCAM/Wide Field Slitless Spectroscopy (2.4-5.0 micron) may be unlikely. However, MIRI observations (5-28 micron) toward COM-rich environments where solid-phase COM abundances exceed 1% with respect to the water ice column density might reveal the distinctive ice features of COMs., Accepted to ApJ (28 Pages, 11 figures)

This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout.

Creating and maintaining computer-readable geometries for use in Monte Carlo Radiation Transport (MCRT) simulations is an error-prone and time-consuming task. Simulating a system often requires geometry from different sources and modelling environments, including a range of MCRT codes and computer-aided design (CAD) tools. Pyg 4 ometry is a Python library that enables users to rapidly create, manipulate, display, debug, read, and write Geometry Description Markup Language (GDML)-based geometry used in MCRT simulations. Pyg 4 ometry provides importation of CAD files to GDML tessellated solids, conversion of GDML geometry to FLUKA and conversely from FLUKA to GDML. The implementation of Pyg 4 ometry is explained in detail in this paper and includes a number of small examples to demonstrate some of its capabilities. The paper concludes with a complete example using most of Pyg 4 ometry's features and a discussion of possible extensions and future work. Program summary Program Title: Pyg 4 ometry CPC Library link to program files: https://doi.org/10.17632/hngmhmh8cx.1 Licensing provisions: GPLv3 Programming language: Python, C++ External routines/libraries: ANTLR, CGAL, FreeCAD, NumPy, OpenCascade, SymPy, VTK Nature of problem: Creating computer-readable geometry descriptions for Monte Carlo radiation transport (MCRT) codes is a time-consuming and error-prone task. Typically these geometries are written by the user directly in the file format used by the MCRT code. There are also multiple MCRT codes available and geometry conversion is difficult or impossible between these simulation tools. Solution method: Create a Python application programming interface for the description and manipulation of Geant4 and FLUKA geometries, with full support for the direct reading and writing of their respective geometry description file formats. Form triangular meshes to represent geometric objects for both visualisation of the geometry and to enable the use of advanced mesh-based geometric algorithms. Triangular mesh processing algorithms allow the loading and use of Standard Triangle Language (STL) and CAD/CAM files. Converting from FLUKA to Geant4 requires algorithms to decompose solids to a set of unions of convex solids. Converting from FLUKA to Geant4 requires a number of steps including the replacement of infinite surfaces with finite solids and the automatic elimination of overlaps.

Beam Delivery Simulation (BDSIM) is a program that simulates the passage of particles in a particle accelerator. It uses a suite of standard high energy physics codes (Geant4, ROOT and CLHEP) to create a computational model of a particle accelerator that combines accurate accelerator tracking routines with all of the physics processes of particles in Geant4. This unique combination permits radiation and detector background simulations in accelerators where both accurate tracking of all particles is required over long range or over many revolutions of a circular machine, as well as interaction with the material of the accelerator., Comment: 20 pages, 17 figures. Accepted for publication 28th Jan 2020

The `Laser-hybrid Accelerator for Radiobiological Applications', LhARA, is conceived as a novel, uniquely-flexible facility dedicated to the study of radiobiology. The technologies demonstrated in LhARA, which have wide application, will be developed to allow particle-beam therapy to be delivered in a completely new regime, combining a variety of ion species in a single treatment fraction and exploiting ultra-high dose rates. LhARA will be a hybrid accelerator system in which laser interactions drive the creation of a large flux of protons or light ions that are captured using a plasma (Gabor) lens and formed into a beam. The laser-driven source allows protons and ions to be captured at energies significantly above those that pertain in conventional facilities, thus evading the current space-charge limit on the instantaneous dose rate that can be delivered. The laser-hybrid approach, therefore, will allow the vast ``terra incognita'' of the radiobiology that determines the response of tissue to ionising radiation to be studied with protons and light ions using a wide variety of time structures, spectral distributions, and spatial configurations at instantaneous dose rates up to and significantly beyond the ultra-high dose-rate `FLASH' regime. It is proposed that LhARA be developed in two stages. In the first stage, a programme of in vitro radiobiology will be served with proton beams with energies between 10MeV and 15MeV. In stage two, the beam will be accelerated using a fixed-field accelerator (FFA). This will allow experiments to be carried out in vitro and in vivo with proton beam energies of up to 127MeV. In addition, ion beams with energies up to 33.4MeV per nucleon will be available for in vitro and in vivo experiments. This paper presents the conceptual design for LhARA and the R&D programme by which the LhARA consortium seeks to establish the facility., 36 pages, 11 figures, preprint submitted to Frontiers in Physics, Medical Physics and Imaging

Complex organic molecules (COMs) are thought to form on icy dust grains in the earliest phase of star formation. The evolution of these COMs from the youngest Class 0/I protostellar phases toward the more evolved Class II phase is still not fully understood. Since planet formation seems to start early, and mature disks are too cold for characteristic COM emission lines, studying the inventory of COMs on solar system scales in the Class 0/I stage is relevant. ALMA Band 3 (3 mm) and Band 6 (1 mm) observations are obtained of seven Class 0 protostars in the Perseus and Serpens star-forming regions. By modeling the inner protostellar region using 'LTE' models, the excitation temperature and column densities are determined for several O-bearing COMs. B1-c, B1-bS, and Serpens S68N show COM emission, i.e, three out of the seven sources. No clear correlation seems to exist between the occurrence of COMs and source luminosity. The abundances of several COMs with respect to CH3OH are remarkably similar for the three COM-rich sources, and to IRAS 16293-2422B and HH 212. For other COMs the abundances differ by up to an order of magnitude, indicating that local source conditions are case determining. B1-c hosts a cold ($T_{ex}\approx60$ K), more extended component of COM emission with a column density of typically a few % of the warm/hot ($T_{ex}\sim 200$ K), central component. A D/H ratio of 1-3 % is derived based on the CH2DOH/CH3OH ratio suggesting a temperature of $\sim$15~K during the formation of methanol. This ratio is consistent with other low-mass protostars. Future mid-infrared facilities such as JWST/MIRI will be essential to directly observe COM ices. Combining this with a larger sample of COM-rich sources with ALMA will allow for directly linking ice and gas-phase abundances in order to constrain the routes that produce and maintain chemical complexity during the star formation process., Accepted to A&A, 44 pages, 17 figures

Isolated dense molecular cores are investigated to study the onset of complex organic molecule formation in interstellar ice. Sampling three cores with ongoing formation of low-mass stars (B59, B335, and L483) and one starless core (L694-2) we sample lines of sight to nine background stars and five young stellar objects (YSOs; A_K ~0.5 - 4.7). Spectra of these stars from 2-5 $\mu$m with NASA's Infrared Telescope Facility (IRTF) simultaneously display signatures from the cores of H$_2$O (3.0 $\mu$m), CH$_3$OH (C-H stretching mode, 3.53 $\mu$m) and CO (4.67 $\mu$m) ices. The CO ice is traced by nine stars in which five show a long wavelength wing due to a mixture of CO with polar ice (CO$_r$), presumably CH$_3$OH. Two of these sight lines also show independent detections of CH$_3$OH. For these we find the ratio of the CH$_3$OH:CO$_r$ is 0.55$\pm$0.06 and 0.73$\pm$0.07 from L483 and L694-2, respectively. The detections of both CO and CH$_3$OH for the first time through lines of sight toward background stars observationally constrains the conversion of CO into CH$_3$OH ice. Along the lines of sight most of the CO exists in the gas phase and $\leq$15% of the CO is frozen out. However, CH$_3$OH ice is abundant with respect to CO (~50%) and exists mainly as a CH$_3$OH-rich CO ice layer. Only a small fraction of the lines of sight contains CH$_3$OH ice, presumably that with the highest density. The high conversion of CO to CH$_3$OH can explain the abundances of CH$_3$OH ice found in later stage Class 1 low mass YSO envelopes (CH$_3$OH:CO$_r$ ~ 0.5-0.6). For high mass YSOs and one Class 0 YSO this ratio varies significantly implying local variations can affect the ice formation. The large CH$_3$OH ice abundance indicates that the formation of complex organic molecules is likely during the pre-stellar phase in cold environments without higher energy particle interactions (e.g. cosmic rays)., Comment: 26 pages, 7 figures, Accepted for publication by ApJ

We have performed a high resolution 4-13 ${\mu}m$ spectral survey of the hot molecular gas associated with the massive protostars AFGL 2591 and AFGL 2136, utilising the Echelon-Cross-Echelle-Spectrograph (EXES) on-board the Stratospheric Observatory for Infrared Astronomy (SOFIA), and the iSHELL instrument and Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared Telescope Facility (IRTF). Here we present results of this survey with analysis of CO, HCN, C$_2$H$_2$, NH$_3$ and CS, deriving the physical conditions for each species. Also from the IRTF, iSHELL data at 3 ${\mu}m$ for AFGL 2591 are presented that show HCN and C$_2$H$_2$ in emission. In the EXES and TEXES data, all species are detected in absorption, and temperatures and abundances are found to be high (600 K and 10$^{-6}$, respectively). Differences of up to an order of magnitude in the abundances of transitions that trace the same ground state level are measured for HCN and C$_2$H$_2$. The mid-infrared continuum is known to originate in a disk, hence we attribute the infrared absorption to arise in the photosphere of the disk. As absorption lines require an outwardly decreasing temperature gradient, we conclude that the disk is heated in the mid-plane by viscous heating due to accretion. We attribute the near-IR emission lines to scattering by molecules in the upper layers of the disk photosphere. The absorption lines trace the disk properties at 50 AU where a high temperature gas-phase chemistry is taking place. Abundances are consistent with chemical models of the inner disk of Herbig disks.

While it has been suggested that there is a connection between the magnetic properties and the internal structure of young stars, there have not been enough magnetic measurements to firmly establish such a correlation at the earliest ages. Here, we contribute to this endeavor by presenting stellar parameters and magnetic field strength measurements of BP Tau and V347 Aur, both stars observed with the near-infrared spectrograph iSHELL. We first test the accuracy of our method by fitting synthetic stellar spectra to a sample of nine main and post-main-sequence stars. We report uncertainties of $\sigma_{\rm Teff}$ = 91 K in temperature and $\sigma_{\rm log(g)}$ = 0.14 in gravity. We then apply the modeling technique to BP Tau and measure a surface magnetic field strength of $\langle \rm B \rangle $ = 2.5$^{+0.15}_{-0.16}$ kG, confirming literature results. For this star, however, we obtain a much lower temperature value than previous optical studies ($\Delta \rm T \sim 400$ K) and interpret this significant temperature difference as due to the relatively higher impact of starspots at near-infrared wavelengths than at optical wavelengths. We further apply this technique to the class I protostellar source V347 Aur and measure for the first time its magnetic field strength $\langle \rm B \rangle = $ 1.36$^{+0.06}_{-0.05}$ kG and its surface gravity log(g) = 3.25$^{+0.14}_{-0.14}$. Lastly, we combine our measurements with pre-main-sequence stellar evolutionary models and illustrate the effects produced by starspots on the retrieved masses and ages of young stars., Comment: 25 pages, 14 figures, 8 tables

We have observed the massive protostar AFGL 2136 IRS 1 in multiple wavelength windows in the near-to-mid-infrared at high ($\sim3$ km s$^{-1}$) spectral resolution using VLT+CRIRES, SOFIA+EXES, and Gemini North+TEXES. There is an abundance of H$_2$O absorption lines from the $\nu_1$ and $\nu_3$ vibrational bands at 2.7 $\mu$m, from the $\nu_2$ vibrational band at 6.1 $\mu$m, and from pure rotational transitions near 10-13 $\mu$m. Analysis of state-specific column densities derived from the resolved absorption features reveals that an isothermal absorbing slab model is incapable of explaining the relative depths of different absorption features. In particular, the strongest absorption features are much weaker than expected, indicating optical depth effects resulting from the absorbing gas being well-mixed with the warm dust that serves as the "background" continuum source at all observed wavelengths. The velocity at which the strongest H$_2$O absorption occurs coincides with the velocity centroid along the minor axis of the compact disk in Keplerian rotation recently observed in H$_2$O emission with ALMA. We postulate that the warm regions of this dust disk dominate the continuum emission at near-to-mid infrared wavelengths, and that H$_2$O and several other molecules observed in absorption are probing this disk. Absorption line profiles are not symmetric, possibly indicating that the warm dust in the disk that produces the infrared continuum has a non-uniform distribution similar to the substructure observed in 1.3 mm continuum emission., Comment: 30 pages, 12 figures, 3 tables, ApJ accepted

Formic acid (HCOOH) and carbon dioxide (CO2) are simple species that have been detected in the interstellar medium. The solid-state formation pathways of these species under experimental conditions relevant to prestellar cores are primarily based off of weak infrared transitions of the HOCO complex and usually pertain to the H2O-rich ice phase, and therefore more experimental data are desired. In this article, we present a new and additional solid-state reaction pathway that can form HCOOH and CO2 ice at 10 K 'non-energetically' in the laboratory under conditions related to the "heavy" CO freeze-out stage in dense interstellar clouds, i.e., by the hydrogenation of an H2CO:O2 ice mixture. This pathway is used to piece together the HCOOH and CO2 formation routes when H2CO or CO reacts with H and OH radicals. Temperature programmed desorption - quadrupole mass spectrometry (TPD-QMS) is used to confirm the formation and pathways of newly synthesized ice species as well as to provide information on relative molecular abundances. Reflection absorption infrared spectroscopy (RAIRS) is additionally employed to characterize reaction products and determine relative molecular abundances. We find that for the conditions investigated in conjunction with theoretical results from the literature, H+HOCO and HCO+OH lead to the formation of HCOOH ice in our experiments. Which reaction is more dominant can be determined if the H+HOCO branching ratio is more constrained by computational simulations, as the HCOOH:CO2 abundance ratio is experimentally measured to be around 1.8:1. H+HOCO is more likely than OH+CO (without HOCO formation) to form CO2. Isotope experiments presented here further validate that H+HOCO is the dominant route for HCOOH ice formation in a CO-rich CO:O2 ice mixture that is hydrogenated. These data will help in the search and positive identification of HCOOH ice in prestellar cores., Comment: Accepted for publication in Astronomy and Astrophysics

The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear $e^+e^-$ collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years., 112 pages, 59 figures; published as CERN Yellow Report Monograph Vol. 2/2018; corresponding editors: Philip N. Burrows, Nuria Catalan Lasheras, Lucie Linssen, Marko Petri\v{c}, Aidan Robson, Daniel Schulte, Eva Sicking, Steinar Stapnes

Sulfur has been observed to be severely depleted in dense clouds leading to uncertainty in the molecules that contain it and the chemistry behind their evolution. Here, we aim to shed light on the sulfur chemistry in young stellar objects (YSOs) by using high-resolution infrared spectroscopy of absorption by the $��_3$ rovibrational band of SO$_2$ obtained with the Echelon-Cross-Echelle Spectrograph on the Stratospheric Observatory for Infrared Astronomy. Using local thermodynamic equilibrium models we derive physical parameters for the SO$_2$ gas in the massive YSO MonR2 IRS3. This yields a SO$_2$/$\mathrm{H}$ abundance lower limit of $5.6\pm0.5\times10^{-7}$, or $>\!4\%$ of the cosmic sulfur budget, and an intrinsic line width (Doppler parameter) of $b, 9 pages, 2 figures, accepted for publication in ApJL

We have performed a 5-8 $\mu$m spectral line survey of the hot molecular core associated with the massive protostar AFGL 2591, using the Echelon-Cross-Echelle Spectrograph (EXES) on the Stratospheric Observatory for Infrared Astronomy (SOFIA). We have supplemented these data with a ground based study in the atmospheric M band around 4.5 $\mu$m using the iSHELL instrument on the Infrared Telescope Facility (IRTF), and the full N band window from 8-13 $\mu$m using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the IRTF. Here we present the first detection of ro-vibrational transitions of CS in this source. The absorption lines are centred on average around -10 kms$^{-1}$ and the line widths of CS compare well with the hot component of $^{13}$CO (around 10 kms$^{-1}$). Temperatures for CS, hot $^{13}$CO and $^{12}$CO v=1-2 agree well and are around 700 K. We derive a CS abundance of 8$\times$10$^{-3}$ and 2$\times$10$^{-6}$ with respect to CO and H$_2$ respectively. This enhanced CS abundance with respect to the surrounding cloud (1$\times$10$^{-8}$) may reflect sublimation of H$_2$S ice followed by gas-phase reactions to form CS. Transitions are in LTE and we derive a density of $>$10$^7$ cm$^{-3}$, which corresponds to an absorbing region of $

Analyses of infrared signatures of CO$_2$ in water dominated ices in the ISM can give information on the physical state of CO$_2$ in icy grains and on the thermal history of the ices themselves. In many sources, CO$_2$ was found in the `pure' crystalline form, as signatured by the splitting in the bending mode absorption profile. To a large extent, pure CO$_2$ is likely to have formed from segregation of CO$_2$ from a CO$_2$:H$_2$O mixture during thermal processing. Previous laboratory studies quantified the temperature dependence of segregation, but no systematic measurement of the concentration dependence of segregation is available. In this study, we measured both the temperature dependence and concentration dependence of CO$_2$ segregation in CO$_2$:H$_2$O mixtures, and found that no pure crystalline CO$_2$ forms if the CO$_2$:H$_2$O ratio is less than 23%. Therefore the segregation of CO$_2$ is not always a good thermal tracer of the ice mantle. We found that the position and width of the broad component of the asymmetric stretching vibrational mode of $^{13}$CO$_2$ change linearly with the temperature of CO$_2$:H$_2$O mixtures, but are insensitive to the concentration of CO$_2$. We recommend using this mode, which will be observable towards low mass protostellar envelopes and dense clouds with the James Webb Space Telescope, to trace the thermal history of the ice mantle, especially when segregated CO$_2$ is unavailable. We used the laboratory measured $^{13}$CO$_2$ profile to analyze the ISO-SWS observations of ice mantles towards Young Stellar Objects, and the astrophysical implications are discussed., 11 pages, 12 figures, ApJ accepted

The formation of methanol (CH3OH) on icy grain mantles during the star formation cycle is mainly associated with the CO freeze-out stage. Yet there are reasons to believe that CH3OH also can form at an earlier period of interstellar ice evolution in CO-poor and H2O-rich ices. This work focuses on CH3OH formation in a H2O-rich interstellar ice environment following the OH-mediated H-abstraction in the reaction, CH4 + OH. Experimental conditions are systematically varied to constrain the CH3OH formation yield at astronomically relevant temperatures. CH4, O2, and hydrogen atoms are co-deposited in an ultrahigh vacuum chamber at 10-20 K. OH radicals are generated by the H + O2 surface reaction. Temperature programmed desorption - quadrupole mass spectrometry (TPD-QMS) is used to characterize CH3OH formation, and is complemented with reflection absorption infrared spectroscopy (RAIRS) for CH3OH characterization and quantitation. CH3OH formation is shown to be possible by the sequential surface reaction chain, CH4 + OH -> CH3 + H2O and CH3 + OH -> CH3OH at 10-20 K. This reaction is enhanced by tunneling, as noted in a recent theoretical investigation (Lamberts et al. 2017). The CH3OH formation yield via the CH4 + OH route versus the CO + H route is approximately 20 times smaller for the laboratory settings studied. The astronomical relevance of the new formation channel investigated here is discussed., Accepted for publication in Astronomy and Astrophysics

Orion BN has a large proper motion and radial velocity with respect to the gas and other stars in the region where it is presumed to have formed. Multiple dynamical interaction scenarios have been proposed to explain this motion. In one case BN is thought to have interacted with stars in the Trapezium cluster, while in another it is thought to have interacted with source I while deeply embedded in molecular gas. If there is dense gas that has been retained in close proximity to BN, it may be evidence that the latter scenario is favored. We observed BN at high spectral resolution in three windows near 6 $��$m using SOFIA/EXES targeting the $��_2$ vibrational band of H$_2$O. Absorption from only three transitions of H$_2$O is detected, and through kinematic analysis is associated with cool, dense foreground gas, not BN itself. We find no evidence for H$_2$O absorption or emission at the systemic velocity of BN., 8 pages, 3 figures, 1 table, accepted for publication in ApJL SOFIA special issue

We present high-spectral resolution observations from 12.96 - 13.33 microns towards Orion IRc2 using the mid-infrared spectrograph, EXES, on SOFIA. These observations probe the physical and chemical conditions of the Orion hot core, which is sampled by a bright, compact, mid-infrared background continuum source in the region, IRc2. All ten of the rovibrational C2H2 transitions expected in our spectral coverage, are detected with high S/N, yielding continuous coverage of the R-branch lines from J=9-8 to J=18-17, including both ortho and para species. Eight of these rovibrational transitions are newly reported detections. The isotopologue, 13CCH2, is clearly detected with high signal-to-noise. This enabled a direct measurement of the 12C/13C isotopic ratio for the Orion hot core of 14 +/- 1 and an estimated maximum value of 21. We also detected several HCN rovibrational lines. The ortho and para C2H2 ladders are clearly separate and tracing two different temperatures, 226 K and 164 K, respectively, with a non-equilibrium ortho to para ratio (OPR) of 1.7 +\- 0.1. Additionally, the ortho and para V_LSR values differ by about 1.8 +/- 0.2 km/s, while, the mean line widths differ by 0.7 +/- 0.2 km/s, suggesting that these species are not uniformly mixed along the line of sight to IRc2. We propose that the abnormally low C2H2 OPR could be a remnant from an earlier, colder phase, before the density enhancement (now the hot core) was impacted by shocks generated from an explosive event 500 yrs ago., accepted for publication in The Astrophysical Journal

It is not well known what drives the chemistry of a protostellar envelope, in particular the role of the stellar mass and the outflows on its chemical enrichment. We study the chemical structure of NGC 1333 IRAS 4A in order to (i) investigate the influence of the outflows on the chemistry, (ii) constrain the age of our object, (iii) compare it with a typical high-mass protostellar envelope. In our analysis we use JCMT line mapping and HIFI pointed spectra. To study the influence of the outflow on the degree of deuteration, we compare JCMT maps of HCO+ and DCO+ with non-LTE (RADEX) models in a region that spatially covers the outflow activity of IRAS 4A. To study the envelope chemistry, we derive empirical molecular abundance profiles for the observed species using the radiative transfer code (RATRAN) and adopting a 1D dust density/temperature profile from the literature. We compare our best-fit observed abundance profiles with the predictions from the time dependent gas grain chemical code (ALCHEMIC). The CO, HCN, HNC and CN abundance require an enhanced UV field which points towards an outflow cavity. The abundances (wrt H2) are 1 to 2 orders of magnitude lower than those observed in the high mass protostellar envelope (AFGL 2591), while they are found to be similar within factors of a few with respect to CO. Differences in UV radiation may be responsible for such chemical differentiation, but temperature differences seem a more plausible explanation. The CH3OH modeled abundance profile points towards an age of > 4x10^4 yrs for IRAS 4A. The spatial distribution of H2D+ differs from that of other deuterated species, indicating an origin from a foreground colder layer (, 26 pages, 23 Figures, 6 tables, accepted for publication in A&A

Context. The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking. Aims. This work provides infrared reference spectra of acetaldehyde (CH$_3$CHO), ethanol (CH$_3$CH$_2$OH), and dimethyl ether (CH$_3$OCH$_3$) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcoming James Webb Space Telescope observations. Methods. Fourier transform transmission spectroscopy (500-4000 cm$^{-1}$ / 20-2.5 $\mu$m, 1.0 cm$^{-1}$ resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15~K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed. Results. We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803 $\mu$m bands are recommended, for ethanol the 11.36 and 7.240 $\mu$m bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011 $\mu$m can be used. All spectra are publicly available in the Leiden Database for Ice., Comment: forthcoming paper in Astronomy & Astrophysics

The exclusive photoproduction of J/psi mesons, gamma p->J/psi p, has been studied in ep collisions with the ZEUS detector at HERA, in the kinematic range 20, Comment: 32 pages, 9 postscript figures added references - corrected typos accepted by EPJC

The exclusive electroproduction of omega mesons, ep -> e omega p, has been studied in the kinematic range 3 pi^+pi^-pi^0. The exclusive (ep -> e omega p) cross section in the above kinematic region is 0.108 +- 0.014(stat.) +- 0.026(syst.) nb. The reaction ep -> e phi p, phi -> pi^+pi^-pi^0, has also been measured. The cross sections, as well as the cross-section ratios omega/rho and omega/phi, are presented as a function of W and Q^2. Thus, for the first time, the properties of omega electroproduction can be compared to those of rho^0, phi and J/psi electroproduction at high W., Comment: 15 pages including 4 figures

SPHEREx is a proposed SMEX mission selected for Phase A. SPHEREx will carry out the first all-sky spectral survey and provide for every 6.2" pixel a spectra between 0.75 and 4.18 $\mu$m [with R$\sim$41.4] and 4.18 and 5.00 $\mu$m [with R$\sim$135]. The SPHEREx team has proposed three specific science investigations to be carried out with this unique data set: cosmic inflation, interstellar and circumstellar ices, and the extra-galactic background light. It is readily apparent, however, that many other questions in astrophysics and planetary sciences could be addressed with the SPHEREx data. The SPHEREx team convened a community workshop in February 2016, with the intent of enlisting the aid of a larger group of scientists in defining these questions. This paper summarizes the rich and varied menu of investigations that was laid out. It includes studies of the composition of main belt and Trojan/Greek asteroids; mapping the zodiacal light with unprecedented spatial and spectral resolution; identifying and studying very low-metallicity stars; improving stellar parameters in order to better characterize transiting exoplanets; studying aliphatic and aromatic carbon-bearing molecules in the interstellar medium; mapping star formation rates in nearby galaxies; determining the redshift of clusters of galaxies; identifying high redshift quasars over the full sky; and providing a NIR spectrum for most eROSITA X-ray sources. All of these investigations, and others not listed here, can be carried out with the nominal all-sky spectra to be produced by SPHEREx. In addition, the workshop defined enhanced data products and user tools which would facilitate some of these scientific studies. Finally, the workshop noted the high degrees of synergy between SPHEREx and a number of other current or forthcoming programs, including JWST, WFIRST, Euclid, GAIA, K2/Kepler, TESS, eROSITA and LSST., Comment: Report of the First SPHEREx Community Workshop, http://spherex.caltech.edu/Workshop.html , 84 pages, 28 figures

Extremely red objects, identified in the early Spitzer Space Telescope observations of the bright-rimmed globule IC 1396A and photometrically classified as Class I protostars Class II T Tauri stars based on their mid-infrared colors, were observed spectroscopically at 5.5 to 38 microns (IRS), at the 22 GHz water maser frequency (GBT), and in the optical (Palomar). The sources photometrically identified as Class I are confirmed as objects dominated by accretion luminosity from dense envelopes, with accretion rates 1e-5 to 1e-6 Msun/yr. The ice/silicate absorption ratio in the envelope is exceptionally low for the IC 1396A protostars, compared to those in nearby star-forming regions, suggesting the envelope chemistry is altered by the radiation field or globule pressure. Only one 22 GHz water maser was detected in IC 1396A; its infrared counterpart has luminosity, accepted to the Astrophysical Journal

IRAS 19312+1950 is a peculiar object that has eluded firm characterization since its discovery, with combined maser properties similar to an evolved star and a young stellar object (YSO). To help determine its true nature, we obtained infrared spectra of IRAS 19312+1950 in the range 5-550 $\mu$m using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 $\mu$m, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: $\approx0.22M_{\odot}$ of material at $280\pm18$ K, and $\approx1.6M_{\odot}$ of material at $157\pm3$ K. The OI 63 $\mu$m line is detected on-source but no significant emission from atomic ions was found. The HIFI observations display shocked, high-velocity gas with outflow speeds up to 90 km s$^{-1}$ along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H$_2$O at 5.8 $\mu$m and CO$_2$ at 15 $\mu$m. The spectral energy distribution is consistent with a massive, luminous ($\sim2\times10^4L_{\odot}$) central source surrounded by a dense, warm circumstellar disk and envelope of total mass $\sim500$-$700M_{\odot}$, with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS 19312+1950 should be classified as an accreting high-mass YSO rather than an evolved star. In light of this reclassification, IRAS 19312+1950 becomes only the 5th high-mass protostar known to exhibit SiO maser activity, and demonstrates that 18 cm OH maser line ratios may not be reliable observational discriminators between evolved stars and YSOs., Comment: 16 pages. Accepted for publication in ApJ

The Compact Linear Collider (CLIC) is a multi-TeV high-luminosity linear e+e- collider under development. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in a staged approach with three centre-of-mass energy stages ranging from a few hundred GeV up to 3 TeV. The first stage will focus on precision Standard Model physics, in particular Higgs and top-quark measurements. Subsequent stages will focus on measurements of rare Higgs processes, as well as searches for new physics processes and precision measurements of new states, e.g. states previously discovered at LHC or at CLIC itself. In the 2012 CLIC Conceptual Design Report, a fully optimised 3 TeV collider was presented, while the proposed lower energy stages were not studied to the same level of detail. This report presents an updated baseline staging scenario for CLIC. The scenario is the result of a comprehensive study addressing the performance, cost and power of the CLIC accelerator complex as a function of centre-of-mass energy and it targets optimal physics output based on the current physics landscape. The optimised staging scenario foresees three main centre-of-mass energy stages at 380 GeV, 1.5 TeV and 3 TeV for a full CLIC programme spanning 22 years. For the first stage, an alternative to the CLIC drive beam scheme is presented in which the main linac power is produced using X-band klystrons., Comment: 57 pages, 27 figures, 12 tables, published as CERN Yellow Report. Updated version: Minor layout changes for print version

Context: HCOOH is one of the more common species in interstellar ices with abundances of 1-5% with respect to solid H2O. Aims: This study aims at characterizing the HCOOH spectral features in astrophysically relevant ice mixtures in order to interpret astronomical data. Methods: The ices are grown under high vacuum conditions and spectra are recorded in transmission using a Fourier transform infrared spectrometer. Pure HCOOH ices deposited at 15 K and 145 K are studied, as well as binary and tertiary mixtures containing H2O, CO, CO2 and CH3OH. The mixture concentrations are varied from 50:50% to ~10:90% for HCOOH:H2O. Binary mixtures of HCOOH:X and tertiary mixtures of HCOOH:H2O:X with X = CO, CO2, and CH3OH, are studied for concentrations of ~10:90% and ~7:67:26%, respectively. Results: Pure HCOOH ice spectra show broad bands which split around 120 K due to the conversion of a dimer to a chain-structure. Broad single component bands are found for mixtures with H2O. Additional spectral components are present in mixtures with CO, CO2 and CH3OH. The resulting peak position, full width at half maximum and band strength depend strongly on ice structure, temperature, matrix constituents and the HCOOH concentration. Comparison of the solid HCOOH 5.9, 7.2, and 8.1 micron features with astronomical data toward the low mass source HH 46 and high mass source W 33A shows that spectra of binary mixtures do not reproduce the observed ice features. However, our tertiary mixtures especially with CH3OH match the astronomical data very well. Thus interstellar HCOOH is most likely present in tertiary or more complex mixtures with H2O, CH3OH and potentially also CO or CO2, providing constraints on its formation., 11 pages, 10 figures, accepted by A&A

We performed Herschel HIFI, PACS and SPIRE observations towards the molecular cloud interacting supernova remnant G349.7+0.2. An extremely broad emission line was detected at 557 GHz from the ground state transition 1_{10}-1_{01} of ortho-water. This water line can be separated into three velocity components with widths of 144, 27 and 4 km/s. The 144 km/s component is the broadest water line detected to date in the literature. This extremely broad line width shows importance of probing shock dynamics. PACS observations revealed 3 additional ortho-water lines, as well as numerous high-J carbon monoxide (CO) lines. No para-water lines were detected. The extremely broad water line is indicative of a high velocity shock, which is supported by the observed CO rotational diagram that was reproduced with a J-shock model with a density of 10^4 cm^{-3} and a shock velocity of 80 km/s. Two far-infrared fine-structure lines, [O~I] at 145 micron and [C~II] line at 157 micron, are also consistent with the high velocity J-shock model. The extremely broad water line could be simply from short-lived molecules that have not been destroyed in high velocity J-shocks; however, it may be from more complicated geometry such as high-velocity water bullets or a shell expanding in high velocity. We estimate the CO and H2O densities, column densities, and temperatures by comparison with RADEX and detailed shock models. Detection of Extremely Broad Water Emission from the molecular cloud interacting Supernova Remnant G349.7+0.2

Infrared ~5--35 um spectra for 40 solar-mass T Tauri stars and 7 intermediate-mass Herbig Ae stars with circumstellar disks were obtained using the Spitzer Space Telescope as part of the c2d IRS survey. This work complements prior spectroscopic studies of silicate infrared emission from disks, which were focused on intermediate-mass stars, with observations of solar-mass stars limited primarily to the 10 um region. The observed 10 and 20 um silicate feature strengths/shapes are consistent with source-to-source variations in grain size. A large fraction of the features are weak and flat, consistent with um-sized grains indicating fast grain growth (from 0.1--1.0 um in radius). In addition, approximately half of the T Tauri star spectra show crystalline silicate features near 28 and 33 um indicating significant processing when compared to interstellar grains. A few sources show large 10-to-20 um ratios and require even larger grains emitting at 20 um than at 10 um. This size difference may arise from the difference in the depth into the disk probed by the two silicate emission bands in disks where dust settling has occurred. The 10 um feature strength vs. shape trend is not correlated with age or Halpha equivalent width, suggesting that some amount of turbulent mixing and regeneration of small grains is occurring. The strength vs. shape trend is related to spectral type, however, with M stars showing significantly flatter 10 um features (larger grain sizes) than A/B stars. The connection between spectral type and grain size is interpreted in terms of the variation in the silicate emission radius as a function of stellar luminosity, but could also be indicative of other spectral-type dependent factors (e.g, X-rays, UV radiation, stellar/disk winds, etc.)., 17 pages, 13 figures, accepted for publication by ApJ, formatted with emulateapj using revtex4 v4.0

Spitzer Space Telescope spectra of the low mass young stellar object (YSO) IRS 46 (L_bol ~ 0.6 L_sun) in Ophiuchus reveal strong vibration-rotation absorption bands of gaseous C2H2, HCN, and CO2. This is the only source out of a sample of ~100 YSO's that shows these features and the first time they are seen in the spectrum of a solar-mass YSO. Analysis of the Spitzer data combined with Keck L- and M-band spectra gives excitation temperatures of > 350 K and abundances of 10(-6)-10(-5) with respect to H2, orders of magnitude higher than those found in cold clouds. In spite of this high abundance, the HCN J=4-3 line is barely detected with the James Clerk Maxwell Telescope, indicating a source diameter less than 13 AU. The (sub)millimeter continuum emission and the absence of scattered light in near-infrared images limits the mass and temperature of any remnant collapse envelope to less than 0.01 M_sun and 100 K, respectively. This excludes a hot-core type region as found in high-mass YSO's. The most plausible origin of this hot gas rich in organic molecules is in the inner (, 4 pages, 4 figures; To appear in Astrophysical Journal Letters

Sensitive 5-38 um Spitzer Space Telescope (SST) and ground based 3-5 um spectra of the embedded low mass protostars B5 IRS1 and HH46 IRS show deep ice absorption bands superposed on steeply rising mid-infrared continua. The ices likely originate in the circumstellar envelopes. The CO2 bending mode at 15 um is a particularly powerful tracer of the ice composition and processing history. Toward these protostars, this band shows little evidence for thermal processing at temperatures above 50 K. Signatures of lower temperature processing are present in the CO and OCN- bands, however. The observed CO2 profile indicates an intimate mixture with H2O, but not necessarily with CH3OH, in contrast to some high mass protostars. This is consistent with the low CH3OH abundance derived from the ground based L band spectra. The CO2/H2O column density ratios are high in both B5 IRS1 and HH46 IRS (~35%). Clearly, the SST spectra are essential to study ice evolution in low mass protostellar environments, and to eventually determine the relation between interstellar and solar system ices., Scheduled for publication in ApJS Sept. 2004, v154 [Spitzer Special issue]. 5 pages, 1 b&w figure, 1 color figure

Cross sections for e^+p charged current deep inelastic scattering at a centre-of-mass energy of 318 GeV have been determined with an integrated luminosity of 60.9pb^-1 collected with the ZEUS detector at HERA. The differential cross sections dsigma/dQ^2, dsigma/dx and dsigma/dy for Q^2>200 GeV^2 are presented. In addition, d^2sigma/dxdQ^2 has been measured in the kinematic range 280 GeV^2 < Q^2 < 17000 GeV^2 and 0.008 < x < 0.42. The predictions of the Standard Model agree well with the measured cross sections. The mass of the W boson propagator is determined to be M_W=78.9 +/- 2.0 (stat.) +/- 1.8 (syst.) +2.0 -1.8 (PDF) GeV from a fit to dsigma/dQ^2. The chiral structure of the Standard Model is also investigated in terms of the (1-y)^2 dependence of the the double-differential cross section. The structure-function F_2^CC has been extracted by combining the measurements presented here with previous ZEUS results from e^-p scattering, extending the measurement obtained in a neutrino-nucleus scattering experiment to a significantly higher Q^2 region., 35 pages, 8 figures (eps), accepted by European Phys. Journal C. Updated with minor changes to the text requested by the journal referee

Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6, where Q^2 is the virtuality of the exchanged boson and x is the Bjorken variable. The Q dependence of the shape variables has been used in conjunction with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative corrections (`power corrections') to investigate the validity of this approach., 7+25 pages, 6 figures

Events with a final-state proton carrying a large fraction of the proton-beam momentum, x_L>0.6, and the square of the transverse momentum p_T^2, Comment: 53 pages, 19 figures; Fig. 19 replaced; some changes to the text. Version accepted by Nuclear Physics B

Freeze-out of the gas phase elements onto cold grains in dense interstellar and circumstellar media builds up ice mantles consisting of molecules that are mostly formed in situ (H2O, NH3, CO2, CO, CH3OH, and more). This review summarizes the detected infrared spectroscopic ice features and compares the abundances across Galactic, extragalactic, and solar system environments. A tremendous amount of information is contained in the ice band profiles. Laboratory experiments play a critical role in the analysis of the observations. Strong evidence is found for distinct ice formation stages, separated by CO freeze out at high densities. The ice bands have proven to be excellent probes of the thermal history of their environment. The evidence for the long-held idea that processing of ices by energetic photons and cosmic rays produces complex molecules is weak. Recent state of the art observations show promise for much progress in this area with planned infrared facilities., Comment: To appear in Annual Review of Astronomy and Astrophysics, volume 53, 2015. Updated 08/May/2015: corrected numbers in elemental budget section, updated references and typos

We present high spectral resolution (~3 km/s) observations of the nu_2 ro-vibrational band of H2O in the 6.086--6.135 micron range toward the massive protostar AFGL 2591 using the Echelon-Cross-Echelle Spectrograph (EXES) on the Stratospheric Observatory for Infrared Astronomy (SOFIA). Ten absorption features are detected in total, with seven caused by transitions in the nu_2 band of H2O, two by transitions in the first vibrationally excited nu_2 band of H2O, and one by a transition in the nu_2 band of H2{18}O. Among the detected transitions is the nu_2 1(1,1)--0(0,0) line which probes the lowest lying rotational level of para-H2O. The stronger transitions appear to be optically thick, but reach maximum absorption at a depth of about 25%, suggesting that the background source is only partially covered by the absorbing gas, or that the absorption arises within the 6 micron emitting photosphere. Assuming a covering fraction of 25%, the H2O column density and rotational temperature that best fit the observed absorption lines are N(H2O)=(1.3+-0.3)*10^{19} cm^{-2} and T=640+-80 K., Comment: 6 pages, 3 figures, 1 table, accepted for publication in ApJL

A (sub-)millimeter line and continuum study of the class I protostar Elias 29 in the Rho Ophiuchi molecular cloud is presented, whose goals are to understand the nature of this source, and to locate the ices that are abundantly present along this line of sight. Within 15-60" beams, several different components contribute to the line emission. Two different foreground clouds are detected, an envelope/disk system and a dense ridge of HCO+ rich material. The latter two components are spatially separated in millimeter interferometer maps. We analyze the envelope/disk system by using inside-out collapse and flared disk models. The disk is in a relatively face-on orientation (, 17 pages, prepared in emulateapj style Scheduled to appear in ApJ 570 n2, 10 May 2002