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Context. The general theory of relativity predicts the redshift of spectral lines in the solar photosphere as a consequence of the gravitational potential of the Sun. This effect can be measured from a solar disk-integrated flux spectrum of the Sun's reflected light on Solar System bodies. Aims. The laser frequency comb (LFC) calibration system attached to the HARPS spectrograph offers the possibility of performing an accurate measurement of the solar gravitational redshift (GRS) by observing the Moon or other Solar System bodies. Here, we analyse the line shift observed in Fe absorption lines from five high-quality HARPS-LFC spectra of the Moon. Methods. We selected an initial sample of 326 photospheric Fe lines in the spectral range between 476–585 nm and measured their line positions and equivalent widths (EWs). Accurate line shifts were derived from the wavelength position of the core of the lines compared with the laboratory wavelengths of Fe lines. We also used a CO5BOLD 3D hydrodynamical model atmosphere of the Sun to compute 3D synthetic line profiles of a subsample of about 200 spectral Fe lines centred at their laboratory wavelengths. We fit the observed relatively weak spectral Fe lines (with EW< 180 mÅ) with the 3D synthetic profiles. Results. Convective motions in the solar photosphere do not affect the line cores of Fe lines stronger than about ∼150 mÅ. In our sample, only 15 Fe I lines have EWs in the range 150< EW(mÅ) < 550, providing a measurement of the solar GRS at 639 ± 14 m s−1, which is consistent with the expected theoretical value on Earth of ∼633.1 m s−1. A final sample of about 97 weak Fe lines with EW < 180 mÅ allows us to derive a mean global line shift of 638 ± 6 m s−1, which is in agreement with the theoretical solar GRS. Conclusions. These are the most accurate measurements of the solar GRS obtained thus far. Ultrastable spectrographs calibrated with the LFC over a larger spectral range, such as HARPS or ESPRESSO, together with a further improvement on the laboratory wavelengths, could provide a more robust measurement of the solar GRS and further testing of 3D hydrodynamical models. [ABSTRACT FROM AUTHOR]

We investigate the activity-induced signals related to rotation and magnetic cycles in late-type stars (FGKM) and analyse the Ca II H&K, the Hα and the radial velocity time series of 55 stars using the spectra from the HARPS public data base and the light curves provided by the All Sky Automated Survey. We search for short-term and long-term periodic signals in the time series of activity indicators as well as in the photometric light curves. Radial velocity data sets are then analysed to determine the presence of activity-induced signals. We measure a radial velocity signal induced by rotational modulation of stellar surface features in 37 stars, from late-F-type to mid-M-type stars.We report an empirical relationship, with some degree of spectral type dependency, between the mean level of chromospheric emission measured by the log10(R′ HK) and the measured radial velocity semi-amplitude. We also report a relationship between the semi-amplitude of the chromospheric measured signal and the semi-amplitude of the radial velocity-induced signal, which strongly depends on the spectral type. We find that for a given strength of chromospheric activity (i.e. a given rotation period), M-type stars tend to induce larger rotation-related radial velocity signals than G- and K-type stars. [ABSTRACT FROM AUTHOR]

Aims. We investigate the photometric modulation induced by magnetic activity cycles and study the relationship between rotation period and activity cycle(s) in late-type (FGKM) stars. Methods. We analysed light curves, spanning up to nine years, of 125 nearby stars provided by the All Sky Automated Survey (ASAS). The sample is mainly composed of low-activity, main-sequence late-A to mid-M-type stars. We performed a search for short (days) and long-term (years) periodic variations in the photometry. We modelled the light curves with combinations of sinusoids to measure the properties of these periodic signals. To provide a better statistical interpretation of our results, we complement our new results with results from previous similar works. Results. We have been able to measure long-term photometric cycles of 47 stars, out of which 39 have been derived with false alarm probabilities (FAP) of less than 0.1 per cent. Rotational modulation was also detected and rotational periods were measured in 36 stars. For 28 stars we have simultaneous measurements of activity cycles and rotational periods, 17 of which are M-type stars. We measured both photometric amplitudes and periods from sinusoidal fits. The measured cycle periods range from 2 to 14 yr with photometric amplitudes in the range of 5-20 mmag. We found that the distribution of cycle lengths for the different spectral types is similar, as the mean cycle is 9.5 yr for F-type stars, 6.7 yr for G-type stars, 8.5 yr for K-type stars, 6.0 yr for early M-type stars, and 7.1 yr for mid-M-type stars. On the other hand, the distribution of rotation periods is completely different, trending to longer periods for later type stars, from a mean rotation of 8.6 days for F-type stars to 85.4 days in mid-M-type stars. The amplitudes induced by magnetic cycles and rotation show a clear correlation. A trend of photometric amplitudes with rotation period is also outlined in the data. The amplitudes of the photometric variability induced by activity cycles of main-sequence GK stars are lower than those of early- and mid-M dwarfs for a given activity index. Using spectroscopic data, we also provide an update in the empirical relationship between the level of chromospheric activity as given by log10 R'HK and the rotation periods. [ABSTRACT FROM AUTHOR]

We report high spatial resolution i' band imaging of the multiple T Tauri system LkHα 262/LkHα 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2-m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkHα 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkHα 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkHα 263 are comoving, that there is orbital motion in the AB pair, and, remarkably, that LkHα 262-263 is a common proper motion system with less than 1 mas yr-1 relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M⊙ and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB. [ABSTRACT FROM AUTHOR]

We determine rotation periods of a sample of 48 late F-type to mid-M dwarf stars using time series high-resolution spectroscopy of the Ca II H&K and H α chromospheric activity indicators. We find good agreement between the rotation periods obtained from each of these two indicators. An empirical relationship between the level of chromospheric emission measured by log10(R'HK) and the spectroscopic rotation periods is reported. This relation is largely independent of the spectral type and the metallicity of the stars and can be used to make a reliable prediction of rotation periods for late K to mid-M dwarfs with low levels of activity. For some stars in the sample, the measured spectroscopic rotation periods coincide, or are very close, to the orbital periods of postulated planets. In such cases, further studies are needed to clarify whether the associated periodic radial velocity signals reveal the existence of planets or are due to magnetic activity. [ABSTRACT FROM AUTHOR]

We present evidence for anomalous microwave emission (AME) in the Pleiades reflection nebula, using data from the seven-year release of the Wilkinson Microwave Anisotropy Probe and from the COSMOSOMAS (Cosmological Structures on Medium Angular Scales) experiment. The flux integrated in a 1° radius around R.A. = 56°.24, decl. = 23°.78 (J2000) is 2.15 ± 0.12 Jy at 22.8 GHz, where AME is dominant. COSMOSOMAS data show no significant emission, but allow one to set upper limits of 0.94 and 1.58 Jy (99.7% confidence level), respectively, at 10.9 and 14.7 GHz, which are crucial to pin down the AME spectrum at these frequencies, and to discard any other emission mechanisms which could have an important contribution to the signal detected at 22.8 GHz. We estimate the expected level of free-free emission from an extinction-corrected Ha template, while the thermal dust emission is characterized from infrared DIRBE data and extrapolated to microwave frequencies. When we deduct the contribution from these two components at 22.8 GHz, the residual flux, associated with AME, is 2.12 ± 0.12 Jy (17.7σ). The spectral energy distribution from 10 to 60 GHz can be accurately fitted with a model of electric dipole emission from small spinning dust grains distributed in two separated phases of molecular and atomic gas, respectively. The dust emissivity, calculated by correlating the 22.8 GHz data with 100 µm data, is found to be 4.36 ± 0.17 µK (MJy sr-1)-1 a value considerably lower than in typical AME clouds, which present emissivities of ~20 µK (MJy sr-1)-1, although higher than the 0.2 µK (MJy sr-1)-1 of the translucent cloud LDN 1780, where AME has recently been claimed. The physical properties of the Pleiades nebula, in particular its low extinction AV ~ 0.4, indicate that this is indeed a much less opaque object than those where AME has usually been studied. This fact, together with the broad knowledge of the stellar content of this region, provides an excellent testbed for AME characterization in physical conditions different from those generally explored up to now. [ABSTRACT FROM AUTHOR]

The potential of combining Adaptive Optics (AO) and Lucky Imaging (LI) to achieve high-precision astrometry and differential photometry in the optical is investigated by conducting observations of the close 0.1 arcsec brown dwarf binary GJ569Bab. We took 50 000 -band images with our LI instrument FastCam attached to NAOMI, the 4.2-m William Herschel Telescope (WHT) AO facility. In order to extract the most of the astrometry and photometry of the GJ569Bab system we have resorted to a PSF fitting technique using the primary star GJ569A as a suitable PSF reference which exhibits an -band magnitude of . The AO+LI observations at WHT were able to resolve the binary system GJ569Bab located at arcsec from GJ569A. We measure a separation of mas and -band magnitudes of and and colours of 2.72 0.08 and 2.83 0.08 for the Ba and Bb components, respectively. Our study rules out the presence of any other companion to GJ569A down to magnitude at distances larger than 1 arcsec. The colours measured are consistent with M8.5-M9 spectral types for the Ba and Bb components. The available dynamical, photometric and spectroscopic data are consistent with a binary system with Ba being slightly (10-20 per cent) more massive than Bb. We obtain new orbital parameters which are in good agreement with those in the literature. [ABSTRACT FROM AUTHOR]

We present observations with the new 11-GHz radiometer of the COSMOSOMAS experiment at the Teide Observatory (Tenerife). The sky region between 0°≤ RA ≤ 360° and 26°≤ Dec. ≤ 49° (ca. 6500 deg2) was observed with an angular resolution of . Two orthogonal independent channels in the receiving system measured total power signals from linear polarizations with a 2-GHz bandwidth. Maps with an average sensitivity of 50 μK per beam have been obtained for each channel. At high Galactic latitude (| b| > 30°) the 11-GHz data are found to contain the expected cosmic microwave background (CMB) as well as extragalactic radiosources, galactic synchrotron and free–free emission, and a dust-correlated component which is likely of Galactic origin. At the angular scales allowed by the window function of the experiment, the 100–240 μm dust-correlated component presents an amplitude Δ T∼ 9–13 μK while the CMB signal is of the order of 27 μK. The spectral behaviour of the dust-correlated signal is examined in the light of previous COSMOSOMAS data at 13–17 GHz and Wilkinson Microwave Anisotropy Probe data at 22–94 GHz in the same sky region. We detect a flattening in the spectral index of this signal below 20 GHz which rules out synchrotron radiation as being responsible for the emission. This anomalous dust emission can be described by a combination of free–free emission and spinning dust models with a flux density peaking around 20 GHz. [ABSTRACT FROM AUTHOR]

Context. ESPRESSO guaranteed time observations (GTOs) at the 8.2m VLT telescope were performed to look for Earth-like exoplanets in the habitable zone of nearby stars. Barnard's star is a primary target within the ESPRESSO GTO as it is the second closest neighbour to our Sun after the α Centauri stellar system. Aims. We present here a large set of 156 ESPRESSO observations of Barnard's star carried out over four years with the goal of exploring periods of shorter than 50 days, thus including the habitable zone (HZ). Methods. Our analysis of ESPRESSO data using Gaussian process (GP) to model stellar activity suggests a long-term activity cycle at 3200 d and confirms stellar activity due to rotation at 140 d as the dominant source of radial velocity (RV) variations. These results are in agreement with findings based on publicly available HARPS, HARPS-N, and CARMENES data. ESPRESSO RVs do not support the existence of the previously reported candidate planet at 233 d. Results. After subtracting the GP model, ESPRESSO RVs reveal several short-period candidate planet signals at periods of 3.15 d, 4.12 d, 2.34 d, and 6.74 d. We confirm the 3.15 d signal as a sub-Earth mass planet, with a semi-amplitude of 55 ± 7 cm s−1, leading to a planet minimum mass mp sin i of 0.37 ± 0.05 M⊕, which is about three times the mass of Mars. ESPRESSO RVs suggest the possible existence of a candidate system with four sub-Earth mass planets in circular orbits with semi-amplitudes from 20 to 47 cm s−1, thus corresponding to minimum masses in the range of 0.17–0.32 M⊕. Conclusions. The sub-Earth mass planet at 3.1533 ± 0.0006 d is in a close-to circular orbit with a semi-major axis of 0.0229 ± 0.0003 AU, thus located inwards from the HZ of Barnard's star, with an equilibrium temperature of 400 K. Additional ESPRESSO observations would be required to confirm that the other three candidate signals originate from a compact short-period planet system orbiting Barnard's star inwards from its HZ. [ABSTRACT FROM AUTHOR]

Reports on the status of the cosmic microwave background experiments on Tenerife. Background on the Tenerife 10 gigahertz (GHz) and 15 GHz maps; CMB signal detected by the interferometer at 33 GHz and a standard CDM model; Optical configuration of the Cosmological Structures on Medium Angular Scales project.

Focuses on evidence that the transient X-ray source V404 Cyg is a low-mass X-ray binary with a black-hole primary. Describes the discovery of lithium in the spectrum of V404 Cyg; Previous report by Wallerstein; Sources of galactic lithium enrichment; Supernova explosions; More.

Presents the evidence for a blackhole in binary system GR) J1655-40 in Scorpio. Discovery of an overabundance of heavy elements in the atmosphere of the star in the binary system as evidence for supernova ejecta; Suggestion that the supernova progenitor has a mass range of 25-40 solar masses.

Reports the discovery of a brown dwarf near the center of the Pleiades star cluster. Luminosity and temperature; Smooth extrapolation of the stellar mass function of Pleiades.

The number of super-Earth and mini-Neptune planet discoveries has increased significantly in the last two decades thanks to transit and radial velocity (RV) surveys. When it is possible to apply both techniques, we can characterise the internal composition of exoplanets, which in turn provides unique insights on their architecture, formation and evolution. We performed a combined photometric and RV analysis of TOI-238 (TYC 6398-132-1), which has one short-orbit super-Earth planet candidate announced by NASA's TESS team. We aim to confirm its planetary nature using radial velocities taken with the ESPRESSO and HARPS spectrographs, to measure its mass, and to detect the presence of other possible planetary companions. We carried out a joint analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously. We detected the signal induced by TOI-238 b in the RV time series, and the presence of a second transiting planet, TOI-238 c, whose signal appears in RV and TESS data. TOI-238 b is a planet with a radius of 1.402−0.086+0.084R⊕ and a mass of 3.40−0.45+0.46M⊕. It orbits at a separation of 0.02118 ± 0.00038 au of its host star, with an orbital period of 1.2730988 ± 0.0000029 days, and has an equilibrium temperature of 1311 ± 28 K. TOI-238 c has a radius of 2.18 ± 0.18 R⊕ and a mass of 6.7 ± 1.1 M⊕. It orbits at a separation of 0.0749 ± 0.0013 au of its host star, with an orbital period of 8.465652 ± 0.000031 days, and has an equilibrium temperature of 696 ± 15 K. The mass and radius of planet b are fully consistent with an Earth-like composition, making it a likely rocky super-Earth. Planet c could be a water-rich planet or a rocky planet with a small H-He atmosphere. [ABSTRACT FROM AUTHOR]

The Andromeda Galaxy (M31) is the Local Group galaxy that is most similar to the Milky Way (MW). The similarities between the two galaxies make M31 useful for studying integrated properties common to spiral galaxies. We use the data from the recent QUIJOTE-MFI Wide Survey, together with new raster observations focused on M31, to study its integrated emission. The addition of raster data improves the sensitivity of QUIJOTE-MFI maps by almost a factor 3. Our main interest is to confirm if anomalous microwave emission (AME) is present in M31, as previous studies have suggested. To do so, we built the integrated spectral energy distribution of M31 between 0.408 and 3000 GHz. We then performed a component separation analysis taking into account synchrotron, free–free, AME, and thermal dust components. AME in M31 is modelled as a log-normal distribution with maximum amplitude, A AME, equal to 1.03 ± 0.32 Jy. It peaks at |${\nu _{\rm AME}}=17.2\pm 3.2{\rm \, GHz}{}$| with a width of W AME = 0.58 ± 0.16. Both the Akaike and Bayesian information criteria find the model without AME to be less than 1 per cent as probable as the one taking AME into consideration. We find that the AME emissivity per 100  |$\mu$| m intensity in M31 is |${\epsilon _{\rm AME}^{\rm 28.4\, GHz}}=9.6\pm 3.1\,\mu$| K MJy−1 sr, similar to that of the MW. We also provide the first upper limits for the AME polarization fraction in an extragalactic object. M31 remains the only galaxy where an AME measurement has been made of its integrated spectrum. [ABSTRACT FROM AUTHOR]

We use the new QUIJOTE-MFI wide survey (11, 13, 17, and 19 GHz) to produce spectral energy distributions (SEDs), on an angular scale of 1°, of the supernova remnants (SNRs) CTB 80, Cygnus Loop, HB 21, CTA 1, Tycho, and HB 9. We provide new measurements of the polarized synchrotron radiation in the microwave range. The intensity and polarization SEDs are obtained and modelled by combining QUIJOTE-MFI maps with ancillary data. In intensity, we confirm the curved spectra of CTB 80 and HB 21 with a break frequency νb at 2.0 |$^{+1.2}_{-0.5}$| and 5.0 |$^{+1.2}_{-1.0}$|  GHz, respectively; and spectral indices above the break of |$-0.6^{+0.04}_{-0.05}$| and |$-0.86^{+0.04}_{-0.05}$|⁠. We provide constraints on the Anomalous Microwave Emission, suggesting that it is negligible towards these SNRs. From a simultaneous intensity and polarization fit, we recover synchrotron spectral indices as flat as −0.24, and the whole sample has a mean and scatter of −0.44 ± 0.12. The polarization fractions have a mean and scatter of 6.1 ± 1.9 per cent. When combining our results with the measurements from other QUIJOTE (Q-U-I JOint TEnerife CMB experiment) studies of SNRs, we find that radio spectral indices are flatter for mature SNRs, and particularly flatter for CTB 80 (⁠|$-0.24^{+0.07}_{-0.06}$|⁠) and HB 21 (⁠|$-0.34^{+0.04}_{-0.03}$|⁠). In addition, the evolution of the spectral indices against the SNRs age is modelled with a power-law function, providing an exponent −0.07 ± 0.03 and amplitude −0.49 ± 0.02 (at 10 kyr), which are conservative with respect to previous studies of our Galaxy and the Large Magellanic Cloud. [ABSTRACT FROM AUTHOR]

This paper considers latest highlights in simultaneous and follow-up optical observations of high energy astrophysical phenomena by MASTER Global Robotic Net. Such extreme Universe sources includes gamma-ray bursts, gravitational wave events, detected by LIGO/Virgo, fast radio bursts, high energy neutrino sources and others. Some of the neutrinos detected by ground-based facilities owe their births to supermassive black holes – blazars, which are in a special anxious state with high statistical reliability. We discovered the effect of a rapid decrease in the brightness of the blazar PKS 0735+17 at the time of the multiple detection of the high-energy neutrino event IceCube-211208A. This decrease in brightness within several hours was detected with a high confidence (SNR 10) in comparison with a multi-day brightening state of the blazar, which was accompanied not only by a maximum increase in the average brightness, but also by an increase in the amplitude of its brightness fluctuations. Additionally, we analyzed all cases of successful observation of blazars around neutrino events and obtained statistically reliable indications of the relationship between neutrino events and optical activity of blazars in the doubled error box at the 4.2 level. [ABSTRACT FROM AUTHOR]

Anomalous microwave emission (AME) is an important emission component between 10 and 60 GHz that is not yet fully understood. It seems to be ubiquitous in our Galaxy and is observed at a broad range of angular scales. Here we use the new QUIJOTE-MFI wide survey data at 11, 13, 17, and 19 GHz to constrain the AME in the Galactic plane (| b | < 10°) on degree scales. We built the spectral energy distribution between 0.408 and 3000 GHz for each of the 5309 0.9° pixels in the Galactic plane, and fitted a parametric model by considering five emission components: synchrotron, free–free, AME, thermal dust and CMB anisotropies. We show that not including QUIJOTE-MFI data points leads to the underestimation (up to 50 per cent) of the AME signal in favour of free–free emission. The parameters describing these components are then intercompared, looking for relations that help to understand AME physical processes. We find median values for the AME width, W AME, and for its peak frequency, νAME, respectively of |$0.560^{+0.059}_{-0.050}$| and |$20.7^{+2.0}_{-1.9}$|  GHz, slightly in tension with current theoretical models. We find spatial variations throughout the Galactic plane for νAME, but only with reduced statistical significance. We report correlations of AME parameters with certain ISM properties, such as that between the AME emissivity (which shows variations with the Galactic longitude) and the interstellar radiation field, and that between the AME peak frequency and dust temperature. Finally, we discuss the implications of our results on the possible molecules responsible for AME. [ABSTRACT FROM AUTHOR]

We report the discovery of a super-Earth orbiting at the inner edge of the habitable zone of the star GJ 625 based on the analysis of the radial-velocity (RV) time series from the HARPS-N spectrograph, consisting of 151 HARPS-N measurements taken over 3.5 yr. GJ 625 b is a planet with a minimum mass Msin i of 2.82 ± 0.51 M⊕ with an orbital period of 14.628 ± 0.013 days at a distance of 0.078 AU from its parent star. The host star is the quiet M2 V star GJ 625, located at 6.5 pc from the Sun. We find the presence of a second radial-velocity signal in the range 74-85 days that we relate to stellar rotation after analysing the time series of Ca II H&K and Hα spectroscopic indicators, the variations of the FWHM of the CCF, and the APT2 photometric light curves. We find no evidence linking the short-period radial-velocity signal to any activity proxy. [ABSTRACT FROM AUTHOR]

We present results from a near-/mid-IR search for submillimetre galaxies over a region of 6230 deg² of the southern sky. We used a cross-correlation of the VISTA Hemispheric Survey (VHS) and the WISE data base to identify bright galaxies (Ks ≤ 18.2) with near-/mid-IR colours similar to those of the high-redshift lensed submm galaxy SMM J2135-0102. We find seven galaxies that fulfil all five adopted near-/mid-IR colour (NMIRQC) criteria and resemble the SED of the reference galaxy at these wavelengths. For these galaxies, which are broadly distributed in the sky, we determined photometric redshifts in the range z = 1.6-3.2. We searched the VHS for clusters of galaxies, which may be acting as gravitational lenses, and found that six out of the seven galaxies are located within 3.5 arcmin of a cluster/group of galaxies. Using the J-Ks versus J sequences, we determine photometric redshifts for these clusters/groups in the range z = 0.2-0.9. We propose the newly identified sources are ultrabright high-redshift lensed SMG candidates. Follow-up observations in the submm and mm are key to determine the ultimate nature of these objects. [ABSTRACT FROM AUTHOR]

We present new medium-resolution spectroscopic observations of the black hole X-ray binary Nova Muscae 1991 taken with X-Shooter spectrograph installed at the 8.2-m VLT telescope. These observations allow us to measure the time of inferior conjunction of the secondary star with the black hole in this system that, together with previous measurements, yield an orbital period decay of Ṗ =−20.7±12.7 ms yr-1 (−24.5 ± 15.1 μs per orbital cycle). This is significantly faster than those previously measured in the other black hole X-ray binaries A0620-00 and XTE J1118+480. No standard black hole X-ray binary evolutionary model is able to explain this extremely fast orbital decay. At this rate, the secondary star would reach the event horizon (as given by the Schwarzschild radius of about 32 km) in roughly 2.7 Myr. This result has dramatic implications on the evolution and lifetime of black hole X-ray binaries. [ABSTRACT FROM AUTHOR]

We present the catalogue of Q-U-I JOint TEnerife (QUIJOTE) Wide Survey radio sources extracted from the maps of the Multi-Frequency Instrument compiled between 2012 and 2018. The catalogue contains 786 sources observed in intensity and polarization, and is divided into two separate sub-catalogues: one containing 47 bright sources previously studied by the Planck collaboration and an extended catalogue of 739 sources either selected from the Planck Second Catalogue of Compact Sources or found through a blind search carried out with a Mexican Hat 2 wavelet. A significant fraction of the sources in our catalogue (38.7 per cent) are within the | b | ≤ 20° region of the Galactic plane. We determine statistical properties for those sources that are likely to be extragalactic. We find that these statistical properties are compatible with currently available models, with a ∼1.8 Jy completeness limit at 11 GHz. We provide the polarimetric properties of (38, 33, 31, 23) sources with P detected above the |$99.99{{\ \rm per\, cent}}$| significance level at (11, 13, 17, 19) GHz respectively. Median polarization fractions are in the 2.8–4.7 per cent range in the 11–19 GHz frequency interval. We do not distinguish between Galactic and extragalactic sources here. The results presented here are consistent with those reported in the literature for flat- and steep-spectrum radio sources. [ABSTRACT FROM AUTHOR]

We present new intensity and polarization maps obtained with the QUIJOTE experiment towards the Galactic regions W49, W51 and IC443, covering the frequency range from 10 to 20 GHz at |$\sim 1\, \text{deg}$| angular resolution, with a sensitivity in the range 35–79  |$\mu \text{K}\, \text{beam}^{-1}$| for total intensity and 13–23  |$\mu \text{K}\, \text{beam}^{-1}$| for polarization. For each region, we combine QUIJOTE maps with ancillary data at frequencies ranging from 0.4 to 3000 GHz, reconstruct the spectral energy distribution and model it with a combination of known foregrounds. We detect anomalous microwave emission (AME) in total intensity towards W49 at 4.7σ and W51 at 4.0σ with peak frequencies |$\nu _{\rm AME}=(20.0\pm 1.4)\, \text{GHz}$| and |$\nu _{\rm AME}=(17.7\pm 3.6)\, \text{GHz}$|⁠ , respectively; this is the first detection of AME towards W51. The contamination from ultracompact H  ii regions to the residual AME flux density is estimated at 10 per cent in W49 and 5 per cent in W51, and does not rule out the AME detection. The polarized SEDs reveal a synchrotron contribution with spectral indices αs = −0.67 ± 0.10 in W49 and αs = −0.51 ± 0.07 in W51, ascribed to the diffuse Galactic emission and to the local supernova remnant, respectively. Towards IC443 in total intensity we measure a broken power-law synchrotron spectrum with cut-off frequency |$\nu _{\rm 0,s}=(114\pm 73)\, \text{GHz}$|⁠ , in agreement with previous studies; our analysis, however, rules out any AME contribution which had been previously claimed towards IC443. No evidence of polarized AME emission is detected in this study. [ABSTRACT FROM AUTHOR]

We present QUIJOTE intensity and polarization maps in four frequency bands centred around 11, 13, 17, and 19 GHz, and covering approximately 29 000 deg2, including most of the northern sky region. These maps result from 9000 h of observations taken between May 2013 and June 2018 with the first QUIJOTE multifrequency instrument (MFI), and have angular resolutions of around 1°, and sensitivities in polarization within the range 35–40 µK per 1° beam, being a factor ∼2–4 worse in intensity. We discuss the data processing pipeline employed, and the basic characteristics of the maps in terms of real space statistics and angular power spectra. A number of validation tests have been applied to characterize the accuracy of the calibration and the residual level of systematic effects, finding a conservative overall calibration uncertainty of 5 per cent. We also discuss flux densities for four bright celestial sources (Tau A, Cas A, Cyg A, and 3C274), which are often used as calibrators at microwave frequencies. The polarization signal in our maps is dominated by synchrotron emission. The distribution of spectral index values between the 11 GHz and WMAP 23 GHz map peaks at β = −3.09 with a standard deviation of 0.14. The measured BB/EE ratio at scales of ℓ = 80 is 0.26 ± 0.07 for a Galactic cut | b | > 10°. We find a positive TE correlation for 11 GHz at large angular scales (ℓ ≲ 50), while the EB and TB signals are consistent with zero in the multipole range 30 ≲ ℓ ≲ 150. The maps discussed in this paper are publicly available. [ABSTRACT FROM AUTHOR]

The QUIJOTE-MFI Northern Hemisphere Wide Survey has provided maps of the sky above declinations −30° at 11, 13, 17, and 19 GHz. These data are combined with ancillary data to produce Spectral Energy Distributions in intensity in the frequency range 0.4–3 000 GHz on a sample of 52 candidate compact sources harbouring anomalous microwave emission (AME). We apply a component separation analysis at 1° scale on the full sample from which we identify 44 sources with high AME significance. We explore correlations between different fitted parameters on this last sample. QUIJOTE-MFI data contribute to notably improve the characterization of the AME spectrum, and its separation from the other components. In particular, ignoring the 10–20 GHz data produces on average an underestimation of the AME amplitude, and an overestimation of the free–free component. We find an average AME peak frequency of 23.6 ± 3.6 GHz, about 4 GHz lower than the value reported in previous studies. The strongest correlation is found between the peak flux density of the thermal dust and of the AME component. A mild correlation is found between the AME emissivity (A AME/τ250) and the interstellar radiation field. On the other hand no correlation is found between the AME emissivity and the free–free radiation Emission Measure. Our statistical results suggest that the interstellar radiation field could still be the main driver of the intensity of the AME as regards spinning dust excitation mechanisms. On the other hand, it is not clear whether spinning dust would be most likely associated with cold phases of the interstellar medium rather than with hot phases dominated by free–free radiation. [ABSTRACT FROM AUTHOR]

This paper considers latest highlights in simultaneous and follow-up optical observations of high energy astrophysical phenomena by MASTER Global Robotic Net. Such extreme Universe sources includes gamma-ray bursts, gravitational wave events, detected by LIGO/Virgo, fast radio bursts, high energy neutrino sources and others. Some of the neutrinos detected by ground-based facilities owe their births to supermassive black holes – blazars, which are in a special anxious state with high statistical reliability. We discovered the effect of a rapid decrease in the brightness of the blazar PKS 0735+17 at the time of the multiple detection of the high-energy neutrino event IceCube-211208A. This decrease in brightness within several hours was detected with a high confidence (SNR 10) in comparison with a multi-day brightening state of the blazar, which was accompanied not only by a maximum increase in the average brightness, but also by an increase in the amplitude of its brightness fluctuations. Additionally, we analyzed all cases of successful observation of blazars around neutrino events and obtained statistically reliable indications of the relationship between neutrino events and optical activity of blazars in the doubled error box at the 4.2 level. [ABSTRACT FROM AUTHOR]

We present the results of the participation of the MASTER Global Robotic Network in the program to support the aLIGO (O1) and LIGO/Virgo (O2 and O3) gravitational-wave experiments in the electromagnetic channel. This study covers the first observing run O1 from September 2015 to January 2016, the second observing run O2 from November 2016 to August 2017 (only LIGO in January–July, joint LIGO/VIRGO (LVC) in August) and the third observing run O3 from April 2019 to April 2020. The main goal of these observations was to, for the first time in the history of astronomy, perform precise localization of gravitational-wave sources, which successfully resulted in the independent discovery of the kilonova using MASTER telescopes in the process of searching for the source of the GW170817 event. In many other events, dozens of optical transients unrelated to gravitational waves have been detected. Nevertheless, the experience of optical localization of gravitational waves is of exceptional importance for the development of a future successful strategy for the localization of gravitational wave events involving relativistic stars. In addition, objects detected in the analysis of huge areas in the sky, determined by the localization errors of the GW source, have been studied in particular detail by telescopes around the world. Objects such as supernovae, novae, active galactic nuclei, dwarf novae and other explosive phenomena in the Universe have been found and analyzed. More than 220 000 deg2 within the region of the most probable localization of a gravitational wave source have been explored by the MASTER Global Robotic Network. This paper reports on the observations of the MA-STER Global Robotic Network for all alert events from the O1, O2, and O3 observing runs. [ABSTRACT FROM AUTHOR]

We report on the earliest detection of the optical transient MASTER OT J123248.62-012924.5 coincident within the error box with the optical and X-ray transient AT2021lfa/ZTF21aayokph. In our images the brightness of the object rises monotonically with confidence. We interpret this transient as a gamma-ray burst (GRB) characterized by smooth optical self-similar (SOSS) emission, while the nondetection of gamma-ray emission at space observatories is interpreted in terms of the hypothesis of a "failed" GRB. Thus, this is the first detection of a nonmonotonic orphan burst. [ABSTRACT FROM AUTHOR]

We report on the high-resolution spectroscopic observations of two planetary transits of the hot Jupiter KELT-7b (M p = 1.28 ± 0.17 M Jup, T eq = 2028 K) observed with the High Optical Resolution Spectrograph (HORuS) mounted on the 10.4-m Gran Telescopio Canarias (GTC). A new set of stellar parameters are obtained for the rapidly rotating parent star from the analysis of the spectra. Using the newly derived stellar mass and radius, and the planetary transit data of the Transiting Exoplanet Survey Satellite (TESS) together with the HORuS velocities and the photometric and spectroscopic data available in the literature, we update and improve the ephemeris of KELT-7b. Our results indicate that KELT-7 has an angle λ = −10.55 ± 0.27 deg between the sky projections of the star's spin axis and the planet's orbital axis. By combining this angle and our newly derived stellar rotation period of 1.38 ± 0.05 d, we obtained a 3D obliquity ψ = 12.4 ± 11.7 deg (or 167.6 deg), thus reinforcing that KELT-7 is a well-aligned planetary system. We search for the presence of H α , Li  i , Na  i , Mg  i , and Ca  ii features in the transmission spectrum of KELT-7b but we are only able to determine upper limits of 0.08–1.4 per cent on their presence after accounting for the contribution of the stellar variability to the extracted planetary spectrum. We also discuss the impact of stellar variability on the planetary data. Our results reinforce the importance of monitoring the parent star when performing high-resolution transmission spectroscopy of the planetary atmosphere in the presence of stellar activity. [ABSTRACT FROM AUTHOR]

In this paper, we present Q-U-I JOint Tenerife Experiment (QUIJOTE) 10–20 GHz observations (194 h in total over ≈250 deg²) in intensity and polarisation of G159.6-18.5, one of the most widely studied regions harbouring anomalous microwave emission (AME). By combining with other publicly available intensity data, we achieve the most precise spectrum of the AME measured to date in an individual region, with 13 independent data points between 10 and 50 GHz being dominated by this emission. The four QUIJOTE data points provide the first independent confirmation of the downturn of the AME spectrum at low frequencies, initially unveiled by the COSMOlogical Structures On Medium Angular Scales experiment in this region. Our polarisation maps, which have an angular resolution of ≈1° and a sensitivity of ≈ 25 μK beam−1, are consistent with zero polarisation. We obtain upper limits on the polarisation fraction of Π < 6.3 and <2.8 percent (95 percent C.L.), respectively, at 12 and 18 GHz (ΠAME < 10.1 and <3.4 percent with respect to the residual AME intensity), a frequency range where no AME polarisation observations have been reported to date. The combination of these constraints with those from other experiments confirm that all the magnetic dust models based on single-domain grains, and most of those considering randomly oriented magnetic inclusions, predict higher polarisation levels than is observed towards regions with AME. Also, neither of the two considered models of electric dipole emission seems to be compatible with all the observations together. More stringent constraints of the AME polarisation at 10–40 GHz are necessary to disentangle between different models, to which future QUIJOTE data will contribute. [ABSTRACT FROM AUTHOR]

We have performed mid-infrared imaging of Barnard's Star, one of the nearest stars to the Sun, using CanariCam on the 10.4 m Gran Telescopio Canarias. We aim to investigate an area within 1-10 arcsec separations, which for the 1.83 pc distance of the star translates to projected orbital separations of 1.8-18 au (P > 12 yr), which have not been explored yet with astrometry or radial velocity programs. It is therefore an opportunity to enter the domain of distances where most giant planets are expected to form. We performed deep imaging in the N-band window (Si-2 filter, 8.7 μm) reaching a 3σ detection limit of 0.85 ± 0.18 mJy and angular resolution of 0.24 arcsec, close to the diffraction limit of the telescope at this wavelength. A total of 80 min on-source integration time data were collected and combined for the deepest image. We achieved a dynamical range of 8.0 ± 0.1 mag in the 8.7 μm band, at angular separations from ~2 to 10 arcsec and of ~6-8 mag at 1-2 arcsec. No additional sources were found. Our detectability limits provide further constraints to the presence of substellar companions of the Barnard's Star. According to solar metallicity evolutionary models, we can exclude companions of masses larger than 15 MJup (Teff > 400 K), ages of a few Gyr, and located in ~3.6-18 au orbits with a 3σ confidence level. This minimum mass is approximately 5 MJup smaller than any previous imaging survey that explored the surroundings of Barnard's Star could restrict. [ABSTRACT FROM AUTHOR]

Aims. The aim of the project is to characterise the two components of the brown dwarf system nearest to the Sun, WISE J104915.57-531906.1 (also called Luhman 16AB) at optical and near-infrared wavelengths. Methods. We obtained high signal-to-noise intermediate-resolution (R ~ 6000-11000) optical (600-1000 nm) and near-infrared (1000-2480 nm) spectra of each component of Luhman 16AB with the X-Shooter instrument on the Very Large Telescope. Results. We classify the primary and secondary of the Luhman 16 system as L6-L7.5 and T0 ± 1, respectively, in agreement with previous measurements published in the literature. We present measurements of the lithium pseudo-equivalent widths, which appear of similar strength in both components (8.2 ± 1.0 A for the L and 8.4 ± 1.5 A for the T component). The presence of lithium (7Li) in both components implies masses lower than 0.06 M0, while the comparison with models suggests lower limits of 0.04 M0. The detection of lithium in the T component is the first of its kind. Similarly, we assess the strength of other alkali lines (e.g. pseudoequivalent widths of 6-7 A for Rbl and 4-7 A for Csl) present in the optical and near-infrared regions and compare with estimates for L and T dwarfs. We also derive effective temperatures and luminosities of each component of the binary: -4.66 ± 0.08 dex and 1305+180 K for the L dwarf and -4.68 ± 0.13 dex and 13 20+135 K for the T dwarf. According to our radial velocity determinations, the binary does not appear to belong to any of the well-known moving group. Our preliminary theoretical analysis of the optical and /-band spectra indicates that the L- and T-type spectra can be reproduced with a single temperature and gravity but different relative chemical abundances, which strongly affects the spectral energy distribution of L/T transition objects. [ABSTRACT FROM AUTHOR]

Aims. The aim of the project is to contribute to the characterisation of the spectral energy distribution of the coolest brown dwarfs discovered to date, the Y dwarfs. Methods. We obtained z-band far-red imaging for six Y dwarfs and a T9+Y0 binary with the OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) instrument on the 10.4-m Gran Telescopio de Canarias (GTC). Results. We detect five of the seven known Y dwarfs in the z-band, infer their optical-to-infrared colours, and measure their proper motions. We find a higher dispersion in the z - J and z - H colours of Y0 dwarfs than in T dwarfs. This dispersion is found to be correlated with H - w2. The high dispersion in the optical-to-infrared colours of Y dwarfs and the possible turnover towards bluer colours may be a consequence of the presence of sulfide clouds with different thicknesses, the depletion of alcalines, and/or gravity effects. [ABSTRACT FROM AUTHOR]

ABSTRACT We report on the discovery of a fourth component in the HD 221356 star system, previously known to be formed by an F8V, a slightly metal poor primary ([Fe/H] = −0.26), and a distant M8V+L3V pair. In our ongoing common proper motion search based on Visible and Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) and Two Micron All Sky Survey (2MASS) catalogues, we have detected a faint J = 13.76 ± 0.04 mag comoving companion of the F8 star located at angular separation of 12.13 ± 0.18 arcsec (position angle of 221°.8 ± 1°.7), corresponding to a projected distance of ∼317 au at 26 pc. Near-infrared spectroscopy of the new companion, covering the 1.5-2.4 μm wavelength range with a resolving power of R ∼ 600, indicates an L1 ± 1 spectral type. Using evolutionary models the mass of the new companion is estimated at ∼0.08 M⊙, which places the object close to the stellar-substellar borderline. This multiple system provides an interesting example of objects with masses slightly above and below the hydrogen-burning mass limit. The low-mass companions of HD 221356 have slightly bluer colours than field dwarfs with similar spectral type, which is likely a consequence of the subsolar metallicity of the system. [ABSTRACT FROM AUTHOR]

We present a deep I, Z photometric survey covering a total area of 1,12 deg² of the σ Orionis cluster and reaching completeness magnitudes of I = 22 and Z = 21.5 mag. From I, I--Z color--magnitude diagrams we have selected 153 candidates that fit the previously known sequence of the cluster. They have magnitudes in the range I = 16-23 mag, which corresponds to a mass interval from 0.1 down to 0.008 M⊙ at the most probable age of σ Orionis (2-4 Myr). Using J-band photometry, we find that 124 of the 151 candidates within the completeness of the optical survey (82%) follow the previously known infrared photometric sequence of the cluster and are probably members. We have studied the spatial distribution of the very low mass stars and brown dwarf population of the cluster and found that there are objects located at distances greater than 30 arcmin to the north and west of σ Orionis that probably belong to different populations of the Orion's Belt, For the 102 bona fide σ Orionis cluster member candidates, we find that the radial surface density can be represented by a decreasing exponential function (σ = σ0e -r/r0) with a central density of σ0 = 0.23 ± 0.03 objects arcmin-2 and a characteristic radius of r0 = 9.5 ± 0.7 arcmin. From a statistical comparison with Monte Carlo simulations, we conclude that the spatial distribution of the objects located at the same distance from the center of the cluster is compatible with a Poissonian distribution and, hence, that very low mass stars and brown dwarfs are not mainly forming aggregations or sub-clustering. Using near-infrared JHK-band data from Two Micron All Sky Survey and UKIRT Deep Infrared Sky Survey and mid-infrared data from Infrared Array Camera/Spitzer, we find that about 5%-9% of the brown dwarf candidates in the σ Orionis cluster have K-band excesses and 30% ± 7% of them show mid-infrared excesses at wavelengths longer than 5.8 µm. These are probably related to the presence of disks, most of which are "transition disks." We have also calculated the initial mass spectrum (dN/dm) of σ Orionis from very low mass stars (~0.10 M⊙) to the deuterium-burning mass limit (0.012-0.013 M⊙), i.e., complete in the entire brown dwarf regime, This mass spectrum is a rising function toward lower masses and can be represented by a power-law distribution (dN/dm ∝ m-α) with an exponent α of 0.7 ± 0.3 for an age of 3 Myr. [ABSTRACT FROM AUTHOR]

We report the discovery of a new broad interstellar (or circumstellar) band at 7088.8 ± 2.0 Å coincident to within the measurement uncertainties with the strongest band of the anthracene cation (C14H ) as measured in gas-phase laboratory spectroscopy at low temperatures. The band is detected in the line of sight of star Cernis 52, a likely member of the very young star cluster IC 348, and is probably associated with cold absorbing material in an intervening molecular cloud of the Perseus star-forming region where various experiments have recently detected anomalous microwave emission. From the measured intensity and available oscillator strength we find a column density of implying that ∼0.008 per cent of the carbon in the cloud could be in the form of C14H . A similar abundance has been recently claimed for the naphthalene cation in this cloud. This is the first location outside the Solar system where specific polycyclic aromatic hydrocarbons (PAHs) are identified. We report observations of interstellar lines of CH and CH+ that support a rather high column density for these species and for molecular hydrogen. The strength ratio of the two prominent diffuse interstellar bands at 5780 and 5797 Å suggests the presence of a ‘zeta’-type cloud in the line of sight (consistent with steep far-ultraviolet extinction and high molecular content). The presence of PAH cations and other related hydrogenated carbon molecules which are likely to occur in this type of clouds reinforces the suggestion that electric dipole radiation from fast-spinning PAHs is responsible of the anomalous microwave emission detected towards Perseus. [ABSTRACT FROM AUTHOR]

We present an analysis of the spectral properties of the extragalactic radio sources in the nearly complete Very Small Array (VSA) sample at 33 GHz. Data from different surveys are used to study source spectra between 1.4 and 33 GHz. We find that, in general, spectra cannot be well described by a single power law in the range of frequencies considered. In particular, most of the VSA sources that are steep between 1.4 and 5 GHz, show a spectral flattening at . We identify 20 objects (19 per cent of the sample) clearly characterized by an upturn spectrum, i.e. a spectrum falling at low frequencies and inverted at higher frequencies. Spectra with high-frequency flattening or upturn shape are supposed to occur when the emission from the active galactic nucleus (AGN) compact core begins to dominate over the component from extended lobes. This picture fits well with the AGN unified scheme, for objects observed at intermediate viewing angles of the AGN jet. Finally, we discuss implications that this class of sources can have on future cosmic microwave background observations at high resolution. [ABSTRACT FROM AUTHOR]

We present the analysis of the first 18 months of data obtained with the COSMOSOMAS (COSMOlogical Structures On Medium Angular Scales) experiment at the Teide Observatory (Tenerife). Three maps have been obtained at 12.7, 14.7 and 16.3 GHz covering 9000 deg2 each with a resolution of ∼1° and with sensitivities 49, 59 and 115 μK beam−1, respectively. These data in conjunction with the Wilkinson Microwave Anisotropy Probe ( WMAP) first year maps have revealed that the cosmic microwave background (CMB) is the dominant astronomical signal at high galactic latitude in the three COSMOSOMAS channels with an average amplitude of (68 per cent c.l. not including calibration errors). This value is in agreement with the predicted CMB signal in the COSMOSOMAS maps using the best-fitting Λ-CDM model to the WMAP power spectrum. Cross-correlation analysis of the 408-MHz map and the COSMOSOMAS data at high galactic latitudes give values in the range from 12.7 to 16.3 GHz. Removing detected point sources in this template, reduces the amplitude of the correlated signal to 8–9 μK. The mean spectral index of the correlated signal between the 408 MHz desourced and the COSMOSOMAS maps is between −3.20 and −2.94 at which indicates that this signal is due to synchrotron emission. Cross-correlation of COSMOSOMAS data with the Diffuse Infrared Background Experiment (DIRBE) map at 100 μm shows the existence of a common signal with amplitude and in the 12.7, 14.7 and 16.3 GHz COSMOSOMAS maps at . Using the WMAP data, we find this DIRBE correlated signal rises from high to low frequencies flattening below ∼20 GHz. At higher galactic latitudes the average amplitude of the correlated signal with the DIRBE maps decreases slightly. The frequency behaviour of the COSMOSOMAS/ WMAP correlated signal with DIRBE is not compatible with the expected tendency for thermal dust. A study of the Hα emission maps do not support free–free as a major contributor to that signal. Our results provide new evidence of a Galactic foreground with properties compatible with predictions by spinning dust models. [ABSTRACT FROM AUTHOR]

We review different surveys, in the optical and infrared, conducted in the very young (age 1–8 Myr), nearby (d ∼ 350 pc) σ Orionis cluster aimed to characterize the substellar population. We describe spectral characteristics of very low mass stars, brown dwarfs and planetary mass objects in the cluster with spectral types from K7 to T6. We study the spatial distribution of the substellar population detected in a IZJ survey covering an area of 1.12 deg.2 We find that the radial distribution of substellar objects can be well fitted by an exponential law (ρ = ρoe-r/ro), with a central density (ρo) of 0.26 ± 0.03 objects/arcmin2 and a characteristic radius (ro) of 8.8 arcmin ± 0.6 (equivalent to 0.90 ± 0.06 pc at the distance of the cluster). We discuss the presence of possible inhomogeneities in this distribution due to the existence of subclustering. We also compare the spatial distribution of the substellar population with previously known stars in the cluster. We report the initial mass spectrum in the substellar domain. [ABSTRACT FROM AUTHOR]

We report an ultrabright lensed submillimeter galaxy at zspec = 1.4796, identified as a result of a full-sky cross-correlation of the AllWISE and Planck compact source catalogs aimed at searching for bright submillimeter galaxies at z ∼ 1.5–2.8. Atacama Pathfinder Experiment (APEX)/LABOCA observations of the candidate galaxy reveal a source with flux S870μm = 54 ± 8 mJy. The position of the APEX source coincides with the position of the AllWISE mid-IR source and with the Einstein ring GAL-CLUS-022058s, observed with the Hubble Space Telescope. Archival VLT/FORS observations reveal the redshift of this Einstein ring, zspec = 1.4796, and the detection of the CO(5–4) line at zspec = 1.4802 with APEX/nFLASH230 confirms the redshift of the submillimeter emission. The lensed source appears to be gravitationally magnified by a massive foreground galaxy cluster lens at z = 0.36. We use Lenstool to model the gravitational lensing, which is close to a "fold arc" configuration for an elliptical mass distribution of the central halo, where four images of the lensed galaxy are seen; the mean magnification is μL = 18 ± 4. We have determined an intrinsic rest-frame infrared luminosity of LIR ≈1012L⊙ and a likely star formation rate of ∼70–170 M⊙yr−1. The molecular gas mass is Mmol ∼ 2.6 × 1010M⊙ and the gas fraction is f = 0.34 ± 0.07. We also obtain a stellar mass log (M*/M⊙) = 10.7 ± 0.1 and a specific star formation rate log (sSFR/Gyr−1) = 0.15 ± 0.03. This galaxy lies on the so-called main sequence of star-forming galaxies at this redshift. [ABSTRACT FROM AUTHOR]

Context. Transiting sub-Neptune-type planets, with radii approximately between 2 and 4 R⊕, are of particular interest as their study allows us to gain insight into the formation and evolution of a class of planets that are not found in our Solar System. Aims. We exploit the extreme radial velocity (RV) precision of the ultra-stable echelle spectrograph ESPRESSO on the VLT to unveil the physical properties of the transiting sub-Neptune TOI-130 b, uncovered by the TESS mission orbiting the nearby, bright, late F-type star HD 5278 (TOI-130) with a period of Pb = 14.3 days. Methods. We used 43 ESPRESSO high-resolution spectra and broad-band photometry information to derive accurate stellar atmospheric and physical parameters of HD 5278. We exploited the TESS light curve and spectroscopic diagnostics to gauge the impact of stellar activity on the ESPRESSO RVs. We performed separate as well as joint analyses of the TESS photometry and the ESPRESSO RVs using fully Bayesian frameworks to determine the system parameters. Results. Based on the ESPRESSO spectra, the updated stellar parameters of HD 5278 are Teff = 6203 ± 64 K, log g = 4.50 ± 0.11 dex, [Fe/H] = −0.12 ± 0.04 dex, M⋆ = 1.126−0.035+0.036 $M_{\star}\,{=}\,1.126_{-0.035}^{+0.036}$ M ⋆   =   1.126 − 0.035 + 0.036 M⊙, and R⋆ = 1.194−0.016+0.017 $R_{\star}\,{=}\,1.194_{-0.016}^{+0.017}$ R ⋆   =   1.194 − 0.016 + 0.017 R⊙. We determine HD 5278 b's mass and radius to be Mb = 7.8−1.4+1.5 $M_{\textrm{b}}\,{=}\,7.8_{-1.4}^{+1.5}$ M b   =   7.8 − 1.4 + 1.5 M⊕ and Rb = 2.45 ± 0.05R⊕. The derived mean density, ϱb = 2.9−0.5+0.6 $\varrho_{\textrm{b}}\,{=}\,2.9_{-0.5}^{+0.6}$ ϱ b   =   2.9 − 0.5 + 0.6 g cm−3, is consistent with the bulk composition of a sub-Neptune with a substantial (~ 30%) water mass fraction and with a gas envelope comprising ~17% of the measured radius. Given the host brightness and irradiation levels, HD 5278 b is one of the best targetsorbiting G-F primaries for follow-up atmospheric characterization measurements with HST and JWST. We discover a second, non-transiting companion in the system, with a period of Pc = 40.87−0.17+0.18 $P_{\textrm{c}}\,{=}\,40.87_{-0.17}^{+0.18}$ P c   =   40.87 − 0.17 + 0.18 days and a minimum mass of Mc sin ic = 18.4−1.9+1.8 $M_{\textrm{c}}\sin\,i_{\textrm{c}} \,{=}\,18.4_{-1.9}^{+1.8}$ M c sin   i c   =   18.4 − 1.9 + 1.8 M⊕. We study emerging trends in parameters space (e.g., mass, radius, stellar insolation, and mean density) of the growing population of transiting sub-Neptunes, and provide statistical evidence for a low occurrence of close-in, 10 − 15M⊕ companions around G-F primaries with Teff ≳ 5500 K. [ABSTRACT FROM AUTHOR]

The High Optical Resolution Spectrograph (HORuS) is a new high-resolution echelle spectrograph available on the 10.4-m Gran Telescopio Canarias (GTC). We report on the first HORuS observations of a transit of the super-Earth planet 55 Cnc e. We investigate the presence of Na  i and Hα in its transmission spectrum and explore the capabilities of HORuS for planetary transmission spectroscopy. Our methodology leads to residuals in the difference spectrum between the in-transit and out-of-transit spectra for the Na  i doublet lines of (3.4 ± 0.4) × 10−4, which sets an upper limit to the detection of line absorption from the planetary atmosphere that is one order of magnitude more stringent that those reported in the literature. We demonstrate that we are able to reach the photon-noise limit in the residual spectra using HORuS to a degree that we would be able to easily detect giant planets with larger atmospheres. In addition, we modelled the structure, chemistry, and transmission spectrum of 55 Cnc e using state-of-the-art open source tools. [ABSTRACT FROM AUTHOR]

We present Keck I/OSIRIS and Keck II/NIRC2 adaptive optics imaging of two member candidates of the Praesepe stellar cluster (d   =  186.18 ± 0.11 pc; 590–790 Myr), UGCS J08451066+2148171 (L1.5 ± 0.5) and UGCS J08301935+2003293 (no spectroscopic classification). We resolved UGCS J08451066+2148171 into a binary system in the near-infrared, with a K -band wavelength flux ratio of 0.89 ± 0.04 and a projected separation of 60.3 ± 1.3 mas (11.2 ± 0.7 au; 1σ). We also resolved UGCS J08301935+2003293 into a binary system with a flux ratio of 0.46 ± 0.03 and a separation of 62.5 ± 0.9 mas. Assuming zero eccentricity, we estimate minimum orbital periods of ∼100 yr for both systems. According to theoretical evolutionary models, we derive masses in the range of 0.074–0.078 and 0.072–0.076 M⊙ for the primary and secondary of UGCS J08451066+2148171 for an age of 700 ± 100 Myr. In the case of UGCS J08301935+2003293, the primary is a low-mass star at the stellar/substellar boundary (0.070–0.078 M⊙), while the companion candidate might be a brown dwarf (0.051–0.065 M⊙). These are the first two binaries composed of L dwarfs in Praesepe. They are benchmark systems to derive the location of the substellar limit at the age and metallicity of Praesepe, determine the age of the cluster based on the lithium depletion boundary test, derive dynamical masses, and improve low-mass stellar and substellar evolutionary models at a well-known age and metallicity. [ABSTRACT FROM AUTHOR]

Context. The bright star π Men was chosen as the first target for a radial velocity follow-up to test the performance of ESPRESSO, the new high-resolution spectrograph at the European Southern Observatory's Very Large Telescope. The star hosts a multi-planet system (a transiting 4 M⊕ planet at ~0.07 au and a sub-stellar companion on a ~2100-day eccentric orbit), which is particularly suitable for a precise multi-technique characterization. Aims. With the new ESPRESSO observations, which cover a time span of 200 days, we aim to improve the precision and accuracy of the planet parameters and search for additional low-mass companions. We also take advantage of the new photometric transits of π Men c observed by TESS over a time span that overlaps with that of the ESPRESSO follow-up campaign. Methods. We analysed the enlarged spectroscopic and photometric datasets and compared the results to those in the literature. We further characterized the system by means of absolute astrometry with HIPPARCOS and Gaia. We used the high-resolution spectra of ESPRESSO for an independent determination of the stellar fundamental parameters. Results. We present a precise characterization of the planetary system around π Men. The ESPRESSO radial velocities alone (37 nightly binned data with typical uncertainty of 10 cm s−1) allow for a precise retrieval of the Doppler signal induced by π Men c. The residuals show a root mean square of 1.2 m s−1, which is half that of the HARPS data; based on the residuals, we put limits on the presence of additional low-mass planets (e.g. we can exclude companions with a minimum mass less than ~2 M⊕ within the orbit of π Men c). We improve the ephemeris of π Men c using 18 additional TESS transits, and, in combination with the astrometric measurements, we determine the inclination of the orbital plane of π Men b with high precision (ib =45.8−1.1+1.4 $i_{b}=45.8^{+1.4}_{-1.1}$ i b = 45.8 − 1.1 + 1.4 deg). This leads to the precise measurement of its absolute mass mb =14.1−0.4+0.5 $m_{b}=14.1^{+0.5}_{-0.4}$ m b = 14.1 − 0.4 + 0.5 MJup, indicating that π Men b can be classified as a brown dwarf. Conclusions. The π Men system represents a nice example of the extreme precision radial velocities that can be obtained with ESPRESSO for bright targets. Our determination of the 3D architecture of the π Men planetary system and the high relative misalignment of the planetary orbital planes put constraints on and challenge the theories of the formation and dynamical evolution of planetary systems. The accurate measurement of the mass of π Men b contributes to make the brown dwarf desert a bit greener. [ABSTRACT FROM AUTHOR]

We present the results of early observations for 130 error-boxes of gamma-ray bursts performed with the Mobile Astronomical System of TElescope-Robots (MASTER) global network of robotic telescopes from Moscow State University in fully automatic mode (2011–2017). Among them, GRB 130907A, GRB 120811C, GRB 110801A, GRB 120404A, GRB 140129B, GRB140311B, and GRB 160227A are considered in details. Among these 130 gamma-ray bursts, in the first 60 s after the trigger with the Swift, Fermi, INTEGRAL, MAXI, Lomonosov, and Konus-Wind orbital observatories, the MASTER was pointed on 51 gamma-ray bursts, being the leader in terms of the first pointing. Full observation automation and MASTER own real-time image processing software allowed us to obtain unique data on early optical emission that accompanied 44 gamma-ray bursts (GRB 110801A, GRB120106A, GRB 120404A, GRB 120811C, GRB 120907A, GRB 121011A, GRB 130122A, GRB 130907A, GRB 131030A, GRB 131125A, GRB 140103A, GRB 140108A, GRB 140129B, GRB 140206A, GRB 140304A, GRB 140311B, GRB 140512A, GRB 140629A, GRB 140801A, GRB140907A, GRB 140930B, GRB141028A, GRB 141225A, GRB 150210A, GRB 150211A, GRB 150301B, GRB 150323C, GRB 150404A/Fermi trigger 449861706, GRB 150403A, GRB 150413A, GRB 150518A, GRB 150627A, GRB 151021A, GRB 151215A, GRB 160104A, GRB 160117B, GRB 160131A, GRB 160227A, GRB 160425A, GRB 160611A, GRB 160625B, GRB 160804A, GRB 160910A, GRB 161017A, GRB 161117A, GRB 161119A). We obtain light curves for 13 gamma-ray bursts among the above listed ones and compare the data in the optical (MASTER), X-ray (Swift-XRT), and hard X-ray (Swift-BAT) ranges. [ABSTRACT FROM AUTHOR]