We report the results of spectrophotometric observations of the massive star MN18 revealed via discovery of a bipolar nebula around it with the Spitzer Space Telescope. Using the optical spectrum obtained with the Southern African Large Telescope, we classify this star as B1 Ia. The evolved status of MN18 is supported by the detection of nitrogen overabundance in the nebula, which implies that it is composed of processed material ejected by the star. We analysed the spectrum of MN18 by using the code CMFGEN, obtaining a stellar effective temperature of approximate to 21 kK. The star is highly reddened, E(B - V) approximate to 2 mag. Adopting an absolute visual magnitude of M-V = -6.8 +/- 0.5 (typical of B1 supergiants), MN18 has a luminosity of log L/L-circle dot approximate to 5.42 +/- 0.30, a mass-loss rate of approximate to(2.8-4.5) x 10(-7) M-circle dot yr(-1), and resides at a distance of approximate to 5.6-(+1.5)(1.2) kpc. We discuss the origin of the nebula around MN18 and compare it with similar nebulae produced by other blue supergiants in the Galaxy (Sher 25, HD 168625, [SBW2007] 1) and the Large Magellanic Cloud (Sk-69 degrees 202). The nitrogen abundances in these nebulae imply that blue supergiants can produce them from the main-sequence stage up to the pre-supernova stage. We also present a K-band spectrum of the candidate luminous blue variable MN56 (encircled by a ring-like nebula) and report the discovery of an OB star at approximate to 17 arcsec from MN18. The possible membership of MN18 and the OB star of the star cluster Lynga 3 is discussed.

The existence of black holes with masses of about one billion solar masses in quasars at redshifts z > 6 presents significant challenges to theories of the formation and growth of black holes and the black hole/galaxy co-evolution in the early Universe. Here we report a recent discovery of an ultra-luminous quasar at redshift z = 6.30, which has an observed optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. With near-infrared spectroscopy, we obtain a black hole mass of about 12 billion solar masses, which is well consistent with the mass derived by assuming an Eddington-limited accretion. This ultra-luminous quasar with at z > 6 provides a unique laboratory to the study of the mass assembly and galaxy formation around the most massive black holes at cosmic dawn. It raises further challenges to the black hole/galaxy co-evolution in the epoch of cosmic reionization because the black hole needs to grow much faster than the host galaxy.

The census of the solar neighbourhood is almost complete for stars and becoming more complete in the brown dwarf regime. Spectroscopic, photometric and kinematic characterization of nearby objects helps us to understand the local mass function, the binary fraction, and provides new targets for sensitive planet searches. We aim to derive spectral types and spectrophotometric distances of a sample of new high proper motion sources found with the WISE (Wide-field Infrared Survey Explorer) satellite, and obtain parallaxes for those objects that fall within the area observed by the Vista Variables in the Via Lactea survey (VVV). We used low-resolution spectroscopy and template fitting to derive spectral types, multiwave-length photometry to characterize the companion candidates and obtain photometric distances. Multi-epoch imaging from the VVV survey was used to measure the parallaxes and proper motions for three sources. We confirm a new T2 brown dwarf within similar to 15 pc. We derived optical spectral types for 24 sources, mostly M dwarfs within 50 pc. We addressed the wide binary nature of 16 objects found by the WISE mission and previously known high proper motion sources. Six of these are probably members of wide binaries, two of those are new, and present evidence against the physical binary nature of two candidate binary stars found in the literature, and eight that we selected as possible binary systems. We discuss a likely microlensing event produced by a nearby low-mass star and a galaxy, that is to occur in the following five years.

Nearly every massive galaxy harbors a supermassive black hole (SMBH) in its nucleus. SMBH masses are millions to billions of solar mass, and they correlate with properties of spheroids of their host galaxies. While the SMBH growth channels, mergers, and gas accretion are well established, their origin remains uncertain: they could have emerged either from massive "seeds" (10(5)-10(6)M(circle dot)) formed by direct collapse of gas clouds in the early universe or from smaller (100M(circle dot)) BHs, end products of first stars. The latter channel would leave behind numerous intermediate-mass BHs (IMBHs, 10(2)-10(5) M-circle dot). Although many IMBH candidates have been identified, none are accepted as definitive; thus, their very existence is still debated. Using data mining in wide-field sky surveys and applying dedicated analysis to archival and follow-up optical spectra, we identified a sample of 305 IMBH candidates having masses 3 x 10(4) M-e < M-BH < 2 x 10(5) M-circle dot, which reside in galaxy centers and are accreting gas that creates characteristic signatures of a type I active galactic nucleus (AGN). We confirmed the AGN nature of 10 sources (including five previously known objects that validate our method) by detecting the X-ray emission from their accretion disks, thus defining the first bona fide sample of IMBHs in galactic nuclei. All IMBH host galaxies possess small bulges and sit on the low-mass extension of the M-BH-M-bulge scaling relation, suggesting that they must have experienced very few if any major mergers over their lifetime. The very existence of nuclear IMBHs supports the stellar-mass seed scenario of the massive BH formation.

Despite extensive efforts, to date only two quasars have been found at z > 7, due to a combination of low spatial density and high contamination from more ubiquitous Galactic cool dwarfs in quasar selection. This limits our current knowledge of the super-massive black hole growth mechanism and reionization history. In this Letter, we report the discovery of a luminous quasar at z = 7.021, DELS J003836.10-152723.6 (hereafter J0038-1527), selected using photometric data from Dark Energy Spectroscopic Instrument Legacy Imaging Survey, Pan-STARRS1 (PS1) imaging Survey, as well as Wide-field Infrared Survey Explore mid-infrared all-sky survey. With an absolute magnitude of M-1450 = -27.1 and bolometric luminosity of L-Bol = 5.6 x 10(13) L-circle dot, J0038-1527 is the most luminous quasar known at z > 7. Deep optical to near-infrared spectroscopic observations suggest that J0038-1527 hosts a 1.3 billion solar mass black hole accreting at the Eddington limit, with an Eddington ratio of 1.25 +/- 0.19. The C IV broad emission line of J0038-1527 is blueshifted by more than 3000 km s(-1) relative to the quasar systemic redshift. More detailed investigations of the high-quality spectra reveal three extremely high-velocity C IV broad absorption lines with velocity from 0.08 to 0.14 times the speed of light and total "balnicity" index of more than 5000 km s(-1), suggesting the presence of relativistic outflows. J0038-1527 is the first quasar found at the epoch of reionization with such strong outflows, and therefore provides a unique laboratory to investigate active galactic nuclei feedback on the formation and growth of the most massive galaxies in the early universe.

This is the fourth paper in a series of publications aiming at discovering quasars at the epoch of reionization. In this paper, we expand our search for z similar to 7 quasars to the footprint of the Dark Energy Survey (DES) Data Release One (DR1), covering similar to 5000 deg(2) of a new area. We select z similar to 7 quasar candidates using deep optical, near-infrared (near-IR) and mid-infrared (mid-IR) photometric data from the DES DR1, the VISTA Hemisphere Survey, the VISTA Kilo-degree Infrared Galaxy survey, the UKIRT InfraRed Deep Sky Surveys-Large Area Survey (ULAS), and the unblurred coadds from the Wide-field Infrared Survey Explore (WISE) images (unWISE). The inclusion of DES and unWISE photometry allows the search to reach similar to 1 mag fainter, comparing to our z greater than or similar to 6.5 quasar survey in the northern sky. We report the initial discovery and spectroscopic confirmation of six new luminous quasars at z > 6.4, including an object at z = 7.02, the fourth quasar yet known at z > 7, from a small fraction of candidates observed thus far. Based on the recent measurement of z similar to 6.7 quasar luminosity function using the quasar sample from our survey in the northern sky, we estimate that there will be greater than or similar to 55 quasars at z > 6.5 at M-1450 < - 24.5 in the full DES footprint.

Context. Ruprecht 147 is the oldest (2.5 Gyr) open cluster in the solar vicinity (<300 pc), making it an important target for stellar evolution studies and exoplanet searches.

Bipolar planetary nebulae (PNe) are thought to result from binary star interactions and, indeed, tens of binary central stars of PNe have been found, in particular using photometric time-series that allow for the detection of post-common envelope systems. Using photometry at the NTT in La Silla we have studied the bright object close to the centre of PN M 3-2 and found it to be an eclipsing binary with an orbital period of 1.88 days. However, the components of the binary appear to be two A or F stars, of almost equal mass, and are therefore too cold to be the source of ionisation of the nebula. Using deep images of the central star obtained in good seeing conditions, we confirm a previous result that the central star is more likely much fainter, located 2 '' away from the bright star. The eclipsing binary is thus a chance alignment on top of the planetary nebula. We also studied the nebular abundance and confirm it to be a Type I PN.

Context. The study of star formation is extremely challenging, due to the lack of complete and clean samples of young nearby clusters and star-forming regions. The recent Gaia DR2 catalogue complemented with the deep ground-based COSMIC DANCe catalogue o ffers a new database of unprecedented accuracy to revisit the membership of clusters and star-forming regions. The 30 Myr open cluster IC 4665 is one of the few well-known clusters of this age and it is an excellent target where evolutionary models can be tested and planetary formation studied.

Atmospheric studies of spectroscopically accessible terrestrial exoplanets lay the groundwork for comparative planetology between these worlds and the solar system terrestrial planets. LHS 3844b is a highly irradiated terrestrial exoplanet (R = 1.303 0.022R(circle plus)) orbiting a mid-M dwarf 15 parsecs away. Work based on near-infrared Spitzer phase curves ruled out atmospheres with surface pressures >= 10 bars on this planet. We present 13 transit observations of LHS 3844b taken with the Magellan Clay telescope and the LDSS3C multi-object spectrograph covering 620-1020 nm. We analyze each of the 13 data sets individually using a Gaussian process regression, and present both white and spectroscopic light curves. In the combined white light curve we achieve an rms precision of 65 ppm when binning to 10 minutes. The mean white light-curve value of (R-p/R-s)(2)is 0.4170 0.0046%. To construct the transmission spectrum, we split the white light curves into 20 spectrophotometric bands, each spanning 20 nm, and compute the mean values of (R-p/R-s)(2)in each band. We compare the transmission spectrum to two sets of atmospheric models. We disfavor a clear, solar composition atmosphere (mu = 2.34) with surface pressures >= 0.1 bar to 5.2 sigma confidence. We disfavor a clear, H2O steam atmosphere (mu = 18) with surface pressures >= 0.1 bar to low confidence (2.9 sigma). Our observed transmission spectrum favors a flat line. For solar composition atmospheres with surface pressures >= 1 bar we rule out clouds with cloud-top pressures of 0.1 bar (5.3 sigma), but we cannot address high-altitude clouds at lower pressures. Our results add further evidence that LHS 3844b is devoid of an atmosphere.