The Messenger Issue 175

DOI: 10.18727/0722-6691/5117

ADS BibCode: 2019Msngr.175....3J

de Jong, R., Agertz, O., Berbel, A., Aird, J., Alexander, D., Amarsi, A., Anders, F., Andrae, R., Ansarinejad, B., Ansorge, W., Antilogus, P., Anwand-Heerwart, H., Arentsen, A., Arnadottir, A., Asplund, M., Auger, M., Azais, N., Baade, D., Baker, G., Baker, S., Balbinot, E., Baldry, I., Banerji, M., Barden, S., Barklem, P., Barthélémy-Mazot, E., Battistini, C., Bauer, S., Bell, C., Bellido-Tirado, O., Bellstedt, S., Belokurov, V., Bensby, T., Bergemann, M., Bestenlehner, J., Bielby, R., Bilicki, M., Blake, C., Bland-Hawthorn, J., Boeche, C., Boland, W., Boller, T., Bongard, S., Bongiorno, A., Bonifacio, P., Boudon, D., Brooks, D., Brown, M., Brown, R., Brüggen, M., Brynnel, J., Brzeski, J., Buchert, T., Buschkamp, P., Caffau, E., Caillier, P., Carrick, J., Casagrande, L., Case, S., Casey, A., Cesarini, I., Cescutti, G., Chapuis, D., Chiappini, C., Childress, M., Christlieb, N., Church, R., Cioni, M., Cluver, M., Colless, M., Collett, T., Comparat, J., Cooper, A., Couch, W., Courbin, F., Croom, S., Croton, D., Daguisé, E., Dalton, G., Davies, L., Davis, T., de Laverny, P., Deason, A., Dionies, F., Disseau, K., Doel, P., Döscher, D., Driver, S., Dwelly, T., Eckert, D., Edge, A., Edvardsson, B., Youssoufi, D., Elhaddad, A., Enke, H., Erfanianfar, G., Farrell, T., Fechner, T., Feiz, C., Feltzing, S., Ferreras, I., Feuerstein, D., Feuillet, D., Finoguenov, A., Ford, D., Fotopoulou, S., Fouesneau, M., Frenk, C., Frey, S., Gaessler, W., Geier, S., Fusillo, N., Gerhard, O., Giannantonio, T., Giannone, D., Gibson, B., Gillingham, P., González-Fernández, C., Gonzalez-Solares, E., Gottloeber, S., Gould, A., Grebel, E., Gueguen, A., Guiglion, G., Haehnelt, M., Hahn, T., Hansen, C., Hartman, H., Hauptner, K., Hawkins, K., Haynes, D., Haynes, R., Heiter, U., Helmi, A., Aguayo, C., Hewett, P., Hinton, S., Hobbs, D., Hoenig, S., Hofman, D., Hook, I., Hopgood, J., Hopkins, A., Hourihane, A., Howes, L., Howlett, C., Huet, T., Irwin, M., Iwert, O., Jablonka, P., Jahn, T., Jahnke, K., Jarno, A., Jin, S., Jofre, P., Johl, D., Jones, D., Jönsson, H., Jordan, C., Karovicova, I., Khalatyan, A., Kelz, A., Kennicutt, R., King, D., Kitaura, F., Klar, J., Klauser, U., Kneib, J., Koch, A., Koposov, S., Kordopatis, G., Korn, A., Kosmalski, J., Kotak, R., Kovalev, M., Kreckel, K., Kripak, Y., Krumpe, M., Kuijken, K., Kunder, A., Kushniruk, I., Lam, M., Lamer, G., Laurent, F., Lawrence, J., Lehmitz, M., Lemasle, B., Lewis, J., Li, B., Lidman, C., Lind, K., Liske, J., Lizon, J., Loveday, J., Ludwig, H., McDermid, R., Maguire, K., Mainieri, V., Mali, S., Mandel, H., Mandel, K., Mannering, L., Martell, S., Martinez Delgado, D., Matijevic, G., McGregor, H., McMahon, R., McMillan, P., Mena, O., Merloni, A., Meyer, M., Michel, C., Micheva, G., Migniau, J., Minchev, I., Monari, G., Muller, R., Murphy, D., Muthukrishna, D., Nandra, K., Navarro, R., Ness, M., Nichani, V., Nichol, R., Nicklas, H., Niederhofer, F., Norberg, P., Obreschkow, D., Oliver, S., Owers, M., Pai, N., Pankratow, S., Parkinson, D., Paschke, J., Paterson, R., Pecontal, A., Parry, I., Phillips, D., Pillepich, A., Pinard, L., Pirard, J., Piskunov, N., Plank, V., Plüschke, D., Pons, E., Popesso, P., Power, C., Pragt, J., Pramskiy, A., Pryer, D., Quattri, M., de Andrade Queiroz, A., Quirrenbach, A., Rahurkar, S., Raichoor, A., Ramstedt, S., Rau, A., Recio-Blanco, A., Reiss, R., Renaud, F., Revaz, Y., Rhode, P., Richard, J., Richter, A., Rix, H., Robotham, A., Roelfsema, R., Romaniello, M., Rosario, D., Rothmaier, F., Roukema, B., Ruchti, G., Rupprecht, G., Rybizki, J., Ryde, N., Saar, A., Sadler, E., Sahlén, M., Salvato, M., Sassolas, B., Saunders, W., Saviauk, A., Sbordone, L., Schmidt, T., Schnurr, O., Scholz, R., Schwope, A., Seifert, W., Shanks, T., Sheinis, A., Sivov, T., Skúladóttir, Á., Smartt, S., Smedley, S., Smith, G., Smith, R., Sorce, J., Spitler, L., Starkenburg, E., Steinmetz, M., Stilz, I., Storm, J., Sullivan, M., Sutherland, W., Swann, E., Tamone, A., Taylor, E., Teillon, J., Tempel, E., ter Horst, R., Thi, W., Tolstoy, E., Trager, S., Traven, G., Tremblay, P., Tresse, L., Valentini, M., van de Weygaert, R., van den Ancker, M., Veljanoski, J., Venkatesan, S., Wagner, L., Wagner, K., Walcher, C., Waller, L., Walton, N., Wang, L., Winkler, R., Wisotzki, L., Worley, C., Worseck, G., Xiang, M., Xu, W., Yong, D., Zhao, C., Zheng, J., Zscheyge, F., Zucker, D.

We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.2 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20 000). After a description of the instrument and its expected performance, a short overview is given of its operational scheme and planned 4MOST Consortium science; these aspects are covered in more detail in other articles in this edition of The Messenger. Finally, the processes, schedules, and policies concerning the selection of ESO Community Surveys are presented, commencing with a singular opportunity to submit Letters of Intent for Public Surveys during the first five years of 4MOST operations.

DOI: 10.18727/0722-6691/5118

ADS BibCode: 2019Msngr.175...12W

Walcher, C., Banerji, M., Battistini, C., Bell, C., Bellido-Tirado, O., Bensby, T., Bestenlehner, J., Boller, T., Brynnel, J., Casey, A., Chiappini, C., Christlieb, N., Church, R., Cioni, M., Croom, S., Comparat, J., Davies, L., de Jong, R., Dwelly, T., Enke, H., Feltzing, S., Feuillet, D., Fouesneau, M., Ford, D., Frey, S., Gonzalez-Solares, E., Gueguen, A., Howes, L., Irwin, M., Klar, J., Kordopatis, G., Korn, A., Krumpe, M., Kushniruk, I., Lam, M., Lewis, J., Lind, K., Liske, J., Loveday, J., Mainieri, V., Martell, S., Matijevic, G., McMahon, R., Merloni, A., Murphy, D., Niederhofer, F., Norberg, P., Pramskiy, A., Romaniello, M., Robotham, A., Rothmaier, F., Ruchti, G., Schnurr, O., Schwope, A., Smedley, S., Sorce, J., Starkenburg, E., Stilz, I., Storm, J., Tempel, E., Thi, W., Traven, G., Valentini, M., van den Ancker, M., Walton, N., Winkler, R., Worley, C.

The 4MOST instrument is a multi-object spectrograph that will address Galactic and extragalactic science cases simultaneously by observing targets from a large number of different surveys within each science exposure. This parallel mode of operation and the survey nature of 4MOST require some distinct 4MOST- specific operational features within the overall operations model of ESO. The main feature is that the 4MOST Consortium will deliver, not only the instrument, but also contractual services to the user community, which is why 4MOST is also described as a facility. This white paper concentrates on information particularly useful to answering the forthcoming Call for Letters of Intent.

DOI: 10.18727/0722-6691/5119

ADS BibCode: 2019Msngr.175...17G

Guiglion, G., Battistini, C., Bell, C., Bensby, T., Boller, T., Chiappini, C., Comparat, J., Christlieb, N., Church, R., Cioni, M., Davies, L., Dwelly, T., de Jong, R., Feltzing, S., Gueguen, A., Howes, L., Irwin, M., Kushniruk, I., Lam, M., Liske, J., McMahon, R., Merloni, A., Norberg, P., Robotham, A., Schnurr, O., Sorce, J., Starkenburg, E., Storm, J., Swann, E., Tempel, E., Thi, W., Worley, C., Walcher, C., The 4MOST Collaboration

The current status of and motivation for the 4MOST survey strategy, as developed by the Consortium science team, are presented here. Key elements of the strategy are described, such as sky coverage, number of visits and total exposure times in different parts of the sky, and how to deal with different observing conditions. The task of organising the strategy is not simple, with many different surveys that have vastly different target brightnesses and densities, sample completeness levels, and signal-to-noise requirements. We introduce here a number of concepts that we will use to ensure all surveys are optimised. Astronomers who are planning to submit a Participating Survey proposal are strongly encouraged to read this article and any relevant 4MOST Survey articles in this issue of The Messenger such that they can optimally complement and benefit from the planned surveys of the 4MOST Consortium.

DOI: 10.18727/0722-6691/5120

ADS BibCode: 2019Msngr.175...23H

Helmi, A., Irwin, M., Deason, A., Balbinot, E., Belokurov, V., Bland-Hawthorn, J., Christlieb, N., Cioni, M., Feltzing, S., Grebel, E., Kordopatis, G., Starkenburg, E., Walton, N., Worley, C.

The goal of this survey is to study the formation and evolution of the Milky Way halo to deduce its assembly history and the 3D distribution of mass in the Milky Way. The combination of multi-band photometry, Gaia proper motion and parallax data, and radial velocities and the metallicity and elemental abundances obtained from low-resolution spectra of halo giants with 4MOST, will yield an unprecedented characterisation of the Milky Way halo and its interface with the thick disc. The survey will produce a volume- and magnitude- limited complete sample of giant stars in the halo. It will cover at least 10 000 square degrees of high Galactic latitude, and measure line-of-sight velocities with a precision of 1–2 km s^–1 as well as metallicities to within 0.2 dex.

DOI: 10.18727/0722-6691/5121

ADS BibCode: 2019Msngr.175...26C

Christlieb, N., Battistini, C., Bonifacio, P., Caffau, E., Ludwig, H., Asplund, M., Barklem, P., Bergemann, M., Church, R., Feltzing, S., Ford, D., Grebel, E., Hansen, C., Helmi, A., Kordopatis, G., Kovalev, M., Korn, A., Lind, K., Quirrenbach, A., Rybizki, J., Skúladóttir, Á., Starkenburg, E.

We will study the formation history of the Milky Way, and the earliest phases of its chemical enrichment, with a sample of more than 1.5 million stars at high galactic latitude. Elemental abundances of up to 20 elements with a precision of better than 0.2 dex will be derived for these stars. The sample will include members of kinematically coherent substructures, which we will associate with their possible birthplaces by means of their abundance signatures and kinematics, allowing us to test models of galaxy formation. Our target catalogue is also expected to contain 30 000 stars at a metallicity of less than one hundredth that of the Sun. This sample will therefore be almost a factor of 100 larger than currently existing samples of metal-poor stars for which precise elemental abundances are available (determined from high-resolution spectroscopy), enabling us to study the early chemical evolution of the Milky Way in unprecedented detail.

DOI: 10.18727/0722-6691/5122

ADS BibCode: 2019Msngr.175...30C

Chiappini, C., Minchev, I., Starkenburg, E., Anders, F., Fusillo, N., Gerhard, O., Guiglion, G., Khalatyan, A., Kordopatis, G., Lemasle, B., Matijevic, G., de Andrade Queiroz, A., Schwope, A., Steinmetz, M., Storm, J., Traven, G., Tremblay, P., Valentini, M., Andrae, R., Arentsen, A., Asplund, M., Bensby, T., Bergemann, M., Casagrande, L., Church, R., Cescutti, G., Feltzing, S., Fouesneau, M., Grebel, E., Kovalev, M., McMillan, P., Monari, G., Rybizki, J., Ryde, N., Rix, H., Walton, N., Xiang, M., Zucker, D., The 4MIDABLE-LR Team

The mechanisms of the formation and evolution of the Milky Way are encoded in the orbits, chemistry and ages of its stars. With the 4MOST MIlky way Disk And BuLgE Low-Resolution Survey (4MIDABLE-LR) we aim to study kinematic and chemical substructures in the Milky Way disc and bulge region with samples of unprecedented size out to larger distances and greater precision than conceivable with Gaia alone or any other ongoing or planned survey. Gaia gives us the unique opportunity for target selection based almost entirely on parallax and magnitude range, hence increasing the efficiency in sampling larger Milky Way volumes with well-defined and effective selection functions.

DOI: 10.18727/0722-6691/5123

ADS BibCode: 2019Msngr.175...35B

Bensby, T., Bergemann, M., Rybizki, J., Lemasle, B., Howes, L., Kovalev, M., Agertz, O., Asplund, M., Barklem, P., Battistini, C., Casagrande, L., Chiappini, C., Church, R., Feltzing, S., Ford, D., Gerhard, O., Kushniruk, I., Kordopatis, G., Lind, K., Minchev, I., McMillan, P., Rix, H., Ryde, N., Traven, G.

The signatures of the formation and evolution of a galaxy are imprinted in its stars. Their velocities, ages, and chemical compositions present major constraints on models of galaxy formation, and on various processes such as the gas inflows and outflows, the accretion of cold gas, radial migration, and the variability of star formation activity. Understanding the evolution of the Milky Way requires large observational datasets of stars via which these quantities can be determined accurately. This is the science driver of the 4MOST MIlky way Disc And BuLgE High-Resolution (4MIDABLE-HR) survey: to obtain high-resolution spectra at < i>R ~ 20 000 and to provide detailed elemental abundances for large samples of stars in the Galactic disc and bulge. High data quality will allow us to provide accurate spectroscopic diagnostics of two million stellar spectra: precise radial velocities; rotation; abundances of many elements, including those that are currently only accessible in the optical, such as Li, s-, and r-process; and multi-epoch spectra for a sub-sample of stars. Synergies with complementary missions like Gaia and TESS will provide masses, stellar ages and multiplicity, forming a multi-dimensional dataset that will allow us to explore and constrain the origin and structure of the Milky Way.

DOI: 10.18727/0722-6691/5124

ADS BibCode: 2019Msngr.175...39F

Finoguenov, A., Merloni, A., Comparat, J., Nandra, K., Salvato, M., Tempel, E., Raichoor, A., Richard, J., Kneib, J., Pillepich, A., Sahlén, M., Popesso, P., Norberg, P., McMahon, R., The 4MOST Collaboration

Groups and clusters of galaxies are a current focus of astronomical research owing to their role in determining the environmental effects on galaxies and the constraints they provide to cosmology. The eROSITA X-ray telescope on board the Spectrum Roentgen Gamma observatory will be launched in 2019 and will have completed eight scans of the full sky when 4MOST starts operating. The experiment will detect groups and clusters of galaxies through X-ray emission from the hot intergalactic medium. The purpose of the 4MOST eROSITA Galaxy Cluster Redshift Survey is to provide spectroscopic redshifts of the optical counterparts to the X-ray emission from 40 000 groups and clusters of galaxies so as to perform dynamical estimates of the total mass and to measure the properties of the member galaxies. The survey aims to obtain precise redshift measurements of the photometrically identified brightest cluster galaxies at redshift z > 0.7. At lower redshifts (z < 0.7) the programme aims to sample over 15 member galaxies per cluster and enable dynamical mass measurements to calibrate the clusters for cosmological experiments. At z < 0.2, eROSITA will also detect X-ray emission from galaxy groups and filaments. 4MOST spectroscopic data from the survey will be used for optical identification of galaxy groups down to eROSITA’s mass detection limits of 10¹³ M_⊙, as well as the detection of the largest filaments for pioneering studies of their X-ray emission.

DOI: 10.18727/0722-6691/5125

ADS BibCode: 2019Msngr.175...42M

Merloni, A., Alexander, D., Banerji, M., Boller, T., Comparat, J., Dwelly, T., Fotopoulou, S., McMahon, R., Nandra, K., Salvato, M., Croom, S., Finoguenov, A., Krumpe, M., Lamer, G., Rosario, D., Schwope, A., Shanks, T., Steinmetz, M., Wisotzki, L., Worseck, G.

X-ray and mid-infrared emission are signposts of the accretion of matter onto the supermassive black holes that reside at the centres of most galaxies. As a major step towards understanding accreting supermassive black holes and their role in the evolution of galaxies, we will use the 4MOST multi-object spectrograph to provide a highly complete census of active galactic nuclei over a large fraction of the extragalactic sky observed in X-rays by eROSITA that is visible to 4MOST. We will systematically follow up all eROSITA point-like extragalactic X-ray sources (mostly active galactic nuclei), and complement them with a heavily obscured active galactic nuclei selection approach using mid-infrared data from the Wide-field Infrared Survey Explorer (WISE). The X-ray and mid-infrared flux limits of eROSITA and WISE are well matched to the spectroscopic capabilities of a 4-metre-class telescope, allowing us to reach completeness levels of ~ 80–90% for all X-ray selected active galactic nuclei with fluxes f_{0.5–2 keV} > 10^–14 erg s^–1 cm^–2; this is about a factor of 30 deeper than the ROSAT all-sky survey. With these data we will determine the physical properties (redshift, luminosity, line emission strength, masses, etc.) of up to one million supermassive black holes, constrain their cosmic evolution and clustering properties, and explore the connection between active galactic nuclei and large-scale structure over redshifts 0 ≲ z ≲ 6.

DOI: 10.18727/0722-6691/5126

ADS BibCode: 2019Msngr.175...46D

Driver, S., Liske, J., Davies, L., Robotham, A., Baldry, I., Brown, M., Cluver, M., Kuijken, K., Loveday, J., McMahon, R., Meyer, M., Norberg, P., Owers, M., Power, C., Taylor, E., The WAVES Team

WAVES is designed to study the growth of structure, mass and energy on scales of ~ 1 kpc to ~ 10 Mpc over a 7 Gyr timeline. On the largest length scales (1–10 Mpc) WAVES will measure the structures defined by groups, filaments and voids, and their emergence over recent times. Comparisons with bespoke numerical simulations will be used to confirm, refine or refute the Cold Dark Matter paradigm. At intermediate length scales (10 kpc^–1 Mpc) WAVES will probe the size and mass distribution of galaxy groups, as well as the galaxy merger rates, in order to directly measure the assembly of dark matter halos and stellar mass. On the smallest length scales (1–10 kpc) WAVES will provide accurate distance and environmental measurements to complement high-resolution space-based imaging to study the mass and size evolution of galaxy bulges, discs and bars. In total, WAVES will provide a panchromatic legacy dataset of ~ 1.6 million galaxies, firmly linking the very low (z < 0.1) and intermediate (z ~ 0.8) redshift Universe.

DOI: 10.18727/0722-6691/5127

ADS BibCode: 2019Msngr.175...50R

Richard, J., Kneib, J., Blake, C., Raichoor, A., Comparat, J., Shanks, T., Sorce, J., Sahlén, M., Howlett, C., Tempel, E., McMahon, R., Bilicki, M., Roukema, B., Loveday, J., Pryer, D., Buchert, T., Zhao, C., The CRS Team

The 4MOST Cosmology Redshift Survey (CRS) will perform stringent cosmological tests via spectroscopic clustering measurements that will complement the best lensing, cosmic microwave background and other surveys in the southern hemisphere. The combination of carefully selected samples of bright galaxies, luminous red galaxies, emission-line galaxies and quasars, totalling about 8 million objects over the redshift range z = 0.15 to 3.5, will allow definitive tests of gravitational physics. Many key science questions will be addressed by combining CRS spectra of these targets with data from current or future facilities such as the Large Synoptic Survey Telescope, the Square Kilometre Array and the Euclid mission.

DOI: 10.18727/0722-6691/5128

ADS BibCode: 2019Msngr.175...54C

Cioni, M., Storm, J., Bell, C., Lemasle, B., Niederhofer, F., Bestenlehner, J., El Youssoufi, D., Feltzing, S., González-Fernández, C., Grebel, E., Hobbs, D., Irwin, M., Jablonka, P., Koch, A., Schnurr, O., Schmidt, T., Steinmetz, M.

The One Thousand and One Magellanic Fields (1001MC) survey aims to measure the kinematics and elemental abundances of many different stellar populations that sample the history of formation and interaction of the Magellanic Clouds. The survey will collect spectra of about half a million stars with G < 19.5 magnitudes (Vega) distributed over an area of about 1000 square degrees and will provide an invaluable dataset for a wide range of scientific applications.

DOI: 10.18727/0722-6691/5129

ADS BibCode: 2019Msngr.175...58S

Swann, E., Sullivan, M., Carrick, J., Hoenig, S., Hook, I., Kotak, R., Maguire, K., McMahon, R., Nichol, R., Smartt, S.

The Time-Domain Extragalactic Survey (TiDES) is focused on the spectro-scopic follow-up of extragalactic optical transients and variable sources selected from forthcoming large sky surveys such as that from the Large Synoptic Survey Telescope (LSST). TiDES contains three sub-surveys: (i) spectroscopic observations of supernova- like transients; (ii) comprehensive follow-up of transient host galaxies to obtain redshift measurements for cosmological applications; and (iii) repeat spectroscopic observations to enable the reverberation mapping of active galactic nuclei. Our simulations predict we will be able to classify transients down to r = 22.5 magnitudes (AB) and, over five years of 4MOST operations, obtain spectra for up to 30 000 live transients to redshift z ~ 0.5, measure redshifts for up to 50 000 transient host galaxies to z ~ 1 and monitor around 700 active galactic nuclei to z ~ 2.5.

DOI: 10.18727/0722-6691/5130

ADS BibCode: 2019Msngr.175...63P

ESO Phase 1 Project Team,

DOI: 10.18727/0722-6691/5131

ADS BibCode: 2019Msngr.175...63E

Sedaghati, E., Miotello, A.

DOI: 10.18727/0722-6691/5132

ADS BibCode: 2019Msngr.175...66E

Zhang, Z.

ADS BibCode: 2019Msngr.175...67E

ESO

ADS BibCode: 2019Msngr.175...69E

ESO