The Messenger

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Highlights include:

Ferrini, F., Wild, W.: The Cherenkov Telescope Array Observatory Comes of Age
Cirasuolo, M., Fairley, A. et al.: MOONS: The New Multi-Object Spectrograph for the VLT
Gonzalez, O., Mucciarelli, A. et al.: MOONS Surveys of the Milky Way and its Satellites
Maiolino, R., Cirasuolo, M. et al.: MOONRISE: The Main MOONS GTO Extragalactic Survey
Béthermin, M., Dessauges-Zavadsky, M. et al.: The ALPINE–ALMA [CII] Survey: Exploring the Dark Side of Normal Galaxies at the End of Reionisation

ADS BibCode: 2020Msngr.180....3F

Ferrini, F., Wild, W.

The Cherenkov Telescope Array (CTA) is the next-generation ground-based observatory for gamma-ray astronomy at very high energies. With up to 120 telescopes on two sites, CTA will be the world’s largest and most sensitive high-energy gamma-ray observatory covering the entire sky. It will consist of a northern array located at the Roque de los Muchachos astronomical observatory on the island of La Palma (Spain) and a southern array near the European Southern Observatory site at Paranal (Chile). Three classes of telescope spread over a large area are required to cover all of CTA’s very-high-energy range from 20 GeV to 300 TeV.

ADS BibCode: 2020Msngr.180...10C

Cirasuolo, M., Fairley, A., Rees, P., Gonzalez, O., Taylor, W., Maiolino, R., Afonso, J., Evans, C., Flores, H., Lilly, S., Oliva, E., Paltani, S., Vanzi, L., Abreu, M., Accardo, M., Adams, N., Álvarez Méndez, D., Amans, J., Amarantidis, S., Atek, H., Atkinson, D., Banerji, M., Barrett, J., Barrientos, F., Bauer, F., Beard, S., Béchet, C., Belfiore, A., Bellazzini, M., Benoist, C., Best, P., Biazzo, K., Black, M., Boettger, D., Bonifacio, P., Bowler, R., Bragaglia, A., Brierley, S., Brinchmann, J., Brinkmann, M., Buat, V., Buitrago, F., Burgarella, D., Burningham, B., Buscher, D., Cabral, A., Caffau, E., Cardoso, L., Carnall, A., Carollo, M., Castillo, R., Castignani, G., Catelan, M., Cicone, C., Cimatti, A., Cioni, M., Clementini, G., Cochrane, W., Coelho, J., Colling, M., Contini, T., Contreras, R., Conzelmann, R., Cresci, G., Cropper, M., Cucciati, O., Cullen, F., Cumani, C., Curti, M., Da Silva, A., Daddi, E., Dalessandro, E., Dalessio, F., Dauvin, L., Davidson, G., de Laverny, P., Delplancke-Ströbele, F., De Lucia, G., Del Vecchio, C., Dessauges-Zavadsky, M., Di Matteo, P., Dole, H., Drass, H., Dunlop, J., Dünner, R., Eales, S., Ellis, R., Enriques, B., Fasola, G., Ferguson, A., Ferruzzi, D., Fisher, M., Flores, M., Fontana, A., Forchi, V., Francois, P., Franzetti, P., Gargiulo, A., Garilli, B., Gaudemard, J., Gieles, M., Gilmore, G., Ginolfi, M., Gomes, J., Guinouard, I., Gutierrez, P., Haigron, R., Hammer, F., Hammersley, P., Haniff, C., Harrison, C., Haywood, M., Hill, V., Hubin, N., Humphrey, A., Ibata, R., Infante, L., Ives, D., Ivison, R., Iwert, O., Jablonka, P., Jakob, G., Jarvis, M., King, D., Kneib, J., Laporte, P., Lawrence, A., Lee, D., Li Causi, G., Lorenzoni, S., Lucatello, S., Luco, Y., Macleod, A., Magliocchetti, M., Magrini, L., Mainieri, V., Maire, C., Mannucci, F., Martin, N., Matute, I., Maurogordato, S., McGee, S., Mcleod, D., McLure, R., McMahon, R., Melse, B., Messias, H., Mucciarelli, A., Nisini, B., Nix, J., Norberg, P., Oesch, P., Oliveira, A., Origlia, L., Padilla, N., Palsa, R., Pancino, E., Papaderos, P., Pappalardo, C., Parry, I., Pasquini, L., Peacock, J., Pedichini, F., Pello, R., Peng, Y., Pentericci, L., Pfuhl, O., Piazzesi, R., Popovic, D., Pozzetti, L., Puech, M., Puzia, T., Raichoor, A., Randich, S., Recio-Blanco, A., Reis, S., Reix, F., Renzini, A., Rodrigues, M., Rojas, F., Rojas-Arriagada, Á., Rota, S., Royer, F., Sacco, G., Sanchez-Janssen, R., Sanna, N., Santos, P., Sarzi, M., Schaerer, D., Schiavon, R., Schnell, R., Schultheis, M., Scodeggio, M., Serjeant, S., Shen, T., Simmonds, C., Smoker, J., Sobral, D., Sordet, M., Spérone, D., Strachan, J., Sun, X., Swinbank, M., Tait, G., Tereno, I., Tojeiro, R., Torres, M., Tosi, M., Tozzi, A., Tresiter, E., Valenti, E., Valenzuela Navarro, Á., Vanzella, E., Vergani, S., Verhamme, A., Vernet, J., Vignali, C., Vinther, J., Von Dran, L., Waring, C., Watson, S., Wild, V., Willesme, B., Woodward, B., Wuyts, S., Yang, Y., Zamorani, G., Zoccali, M., Bluck, A., Trussler, J.

MOONS is the new Multi-Object Optical and Near-infrared Spectrograph currently under construction for the Very Large Telescope (VLT) at ESO. This remarkable instrument combines, for the first time, the collecting power of an 8-m telescope, 1000 fibres with individual robotic positioners, and both low- and high-resolution simultaneous spectral coverage across the 0.64–1.8 μm wavelength range. This facility will provide the astronomical community with a powerful, world-leading instrument able to serve a wide range of Galactic, extragalactic and cosmological studies. Construction is now proceeding full steam ahead and this overview article presents some of the science goals and the technical description of the MOONS instrument. More detailed information on the MOONS surveys is provided in the other dedicated articles in this Messenger issue.

ADS BibCode: 2020Msngr.180...18G

Gonzalez, O., Mucciarelli, A., Origlia, L., Schultheis, M., Caffau, E., Di Matteo, P., Randich, S., Recio-Blanco, A., Zoccali, M., Bonifacio, P., Dalessandro, E., Schiavon, R., Pancino, E., Taylor, W., Valenti, E., Rojas-Arriagada, Á., Sacco, G., Biazzo, K., Bellazzini, M., Cioni, M., Clementini, G., Contreras Ramos, R., de Laverny, P., Evans, C., Haywood, M., Hill, V., Ibata, R., Lucatello, S., Magrini, L., Martin, N., Nisini, B., Sanna, N., Cirasuolo, M., Maiolino, R., Afonso, J., Lilly, S., Flores, H., Oliva, E., Paltani, S., Vanzi, L.

The study of resolved stellar populations in the Milky Way and other Local Group galaxies can provide us with a fossil record of their chemo-dynamical and star-formation histories over timescales of many billions of years. In the galactic components and stellar systems of the Milky Way and its satellites, individual stars can be resolved. Therefore, they represent a unique laboratory in which to investigate the details of the processes behind the formation and evolution of the disc and dwarf/irregular galaxies. MOONS at the VLT represents a unique combination of an efficient infrared multi-object spectrograph and a large-aperture 8-m-class telescope which will sample the cool stellar populations of the dense central regions of the Milky Way and its satellites, delivering accurate radial velocities, metallicities, and other chemical abundances for several millions of stars over its lifetime (see Cirasuolo et al., p. 10). MOONS will observe up to 1000 targets across a 25-arcminute field of view in the optical and near-infrared (0.6–1.8 µm) simultaneously. A high-resolution (R ~ 19700) setting in the H band has been designed for the accurate determination of stellar abundances such as alpha, light, iron-peak and neutron-capture elements.

ADS BibCode: 2020Msngr.180...24M

Maiolino, R., Cirasuolo, M., Afonso, J., Bauer, F., Bowler, R., Cucciati, O., Daddi, E., De Lucia, G., Evans, C., Flores, H., Gargiulo, A., Garilli, B., Jablonka, P., Jarvis, M., Kneib, J., Lilly, S., Looser, T., Magliocchetti, M., Man, Z., Mannucci, F., Maurogordato, S., McLure, R., Norberg, P., Oesch, P., Oliva, E., Paltani, S., Pappalardo, C., Peng, Y., Pentericci, L., Pozzetti, L., Renzini, A., Rodrigues, M., Royer, F., Serjeant, S., Vanzi, L., Wild, V., Zamorani, G.

The MOONS instrument possesses an exceptional combination of large multiplexing, high sensitivity, broad simultaneous spectral coverage (from optical to near-infrared bands), large patrol area and high fibre density. These properties provide the unprecedented potential of enabling, for the very first time, SDSS-like surveys around Cosmic Noon (z ~ 1–2.5), when the star formation rate in the Universe peaked. The high-quality spectra delivered by MOONS will sample the same nebular and stellar diagnostics observed in extensive surveys of local galaxies, providing an accurate and consistent description of the evolution of various physical properties of galaxies, and hence a solid test of different scenarios of galaxy formation and transformation. Most importantly, by spectroscopically identifying hundreds of thousands of galaxies at high redshift, the MOONS surveys will be capable of determining the environments in which primeval galaxies lived and will reveal how such environments affected galaxy evolution. In this article, we specifically focus on the main Guaranteed Time Observation (GTO) MOONS extragalactic survey, MOONRISE, by providing an overview of its scientific goals and observing strategy.

ADS BibCode: 2020Msngr.180...31B

Béthermin, M., Dessauges-Zavadsky, M., Faisst, A., Ginolfi, M., Gruppioni, C., Jones, G., Khusanova, Y., Lemaux, B., Capak, P., Cassata, P., Le Fèvre, O., Schaerer, D., Silverman, J., Yan, L., The Alpine collaboration

Cold gas and cosmic dust are the fuel of star formation. ALPINE is an ALMA Large Programme which has built the first statistically representative sample of star-forming galaxies in the adolescent Universe by targeting emission from singly ionised carbon [CII] at 158 µm, which traces both emission from star-forming regions and molecular hydrogen gas clouds, and the thermal continuum from dust at the end of the epoch of reionisation (4.4 < z < 5.9). Observations by the ALPINE team have revealed that a significant fraction of the star formation at this epoch is already hidden by dust clouds. ALPINE observations have also shown how unruly these young galaxies were by finding a large fraction of mergers and ubiquitous gas outflows.

ADS BibCode: 2020Msngr.180...37T

Triaud, A., Burgasser, A., Burdanov, A., Hodžić, V., Alonso, R., Bardalez Gagliuffi, D., Delrez, L., Demory, B., de Wit, J., Ducrot, E., Hessman, F., Husser, T., Jehin, E., Pedersen, P., Queloz, D., McCormac, J., Murray, C., Sebastian, D., Thompson, S., Van Grootel, V., Gillon, M.

Brown dwarfs — stellar objects unable to sustain hydrogen fusion in their cores because of their low masses — continuously cool over their lifetimes. Evolution models have been created to reproduce this behaviour, and to allow mass and age determination using their luminosity, temperatures, spectral types and other parameters. However, these models have not yet been fully validated or calibrated with observations. During a commissioning run of the SPECULOOS telescopes, we serendipitously discovered a rare double-line eclipsing binary, a member of the 45 Myr-old moving group Argus. This discovery permitted us to determine the masses, radii and ages of the brown dwarfs, and with their luminosities make a comparison to evolution models. The models reproduce these measurements remarkably well, although a measured offset in luminosity could result in systematic underestimation of brown dwarf masses by 20 to 30%. Calibrating these models is necessary as they are also used to infer the masses of young, directly imaged exoplanets such as those found at the VLT.

ADS BibCode: 2020Msngr.180...42K

The Atacama Large Millimeter/submillimeter Array (ALMA) is the largest and most sensitive millimetre/submillimetre array on the planet, with the highest spatial resolution. Since it began operating, ALMA has routinely been at the forefront of science in this wavelength regime, delivering ground-breaking discoveries. The ALMA 2019 science conference was organised as one of a series of meetings held at regular intervals for the worldwide ALMA community, the previous one being held in Indian Wells, USA in 2016. At the start of Cycle 7 of observations, the ALMA 2019 conference provided an opportunity for the community to reflect on the multitude of scientific results from the facility, with special emphasis on the results from the first rounds of ALMA Large Programmes, the long baselines and high-frequency capabilities, the new solar and very long baseline interferometry (VLBI) modes, as well as the synergy between ALMA and other observatories.

ADS BibCode: 2020Msngr.180...46P

Pompei, E., Hartke, J., Korhonen, H., Mazzucchelli, C., Navarrete, C., Pala, A., Sbordone, L., Schmidtobreick, L.

The La Silla Observing Summer School was originally conceived with the goal of providing hands-on training in the use of telescopes and astronomical instruments for senior masters and young doctoral students. The third La Silla Summer School ran over two weeks and was hosted by ESO’s Office for Science and the La Silla Observatory. Twenty PhD and MSc students from several countries participated. They attended lectures on various observing modes and instrumentation but also on scientific presentations, time management, effective proposal writing, and career choices. For the hands-on part at the observatory, the students were supervised by seven ESO tutors. Four small research projects were offered, using three telescopes and four instruments. The students in each research group went through the full process of defining and discussing the observing strategies, conducting the observations, reducing and analysing the data and finally presenting the results to the scientific community at the ESO Vitacura offices. The next school is foreseen for the southern summer break of 2022.

ADS BibCode: 2020Msngr.180...50L

del P. Lagos, C., Robotham, A., De Breuck, C.

We report on the second joint Australia–ESO conference, held in Perth, Australia, following the successful Sydney conference in 2019. The conference was supported by ESO, the Centre of Excellence ASTRO 3D, the International Centre for Radio Astronomy Research, Macquarie University, CSIRO Astronomy and Space Science (CASS), and the Galaxies Journal. The scientific organising committee (SOC) focused on a programme that highlighted the complementarity between ESO and Australian instruments and the science breakthroughs enabled by this combination. In terms of demographics, we followed the same strategies as the previous meeting to tackle unconscious bias, and this again resulted in a well- balanced programme in terms of gender, career stage and geography, proving its effectiveness. Given concerns about global warming and the COVID-19 pandemic, the local organising committee (LOC) allowed several talks to be delivered remotely, and we reflect on that experience here.

ADS BibCode: 2020Msngr.180...53E

Herenz, E., Mazzucchelli, C.

ADS BibCode: 2020Msngr.180...55E

The Messenger Issue 180