We present high-resolution 12CO and 13CO 2–1 ALMA observations, as well as optical and near-infrared spectroscopy, of the highly inclined protoplanetary disk around SSTC2D J163131.2–242627. The spectral type we derive for the source is consistent with a 1.2 M ⊙ star inferred from the ALMA observations. Despite its massive circumstellar disk, we find little to no evidence for ongoing accretion on the star. The CO maps reveal a disk that is unusually compact along the vertical direction, consistent with its appearance in scattered light images. The gas disk extends about twice as far away as both the submillimeter continuum and the optical scattered light. CO is detected from two surface layers separated by a midplane region in which CO emission is suppressed, as expected from freeze-out in the cold midplane. We apply a modified version of the tomographically reconstructed distribution method presented by Dutrey et al. to derive the temperature structure of the disk. We find a temperature in the CO-emitting layers and the midplane of ∼33 K and ∼20 K at R < 200 au, respectively. Outside of R > 200 au, the disk’s midplane temperature increases to ∼30 K, with a nearly vertically isothermal profile. The transition in CO temperature coincides with a dramatic reduction in the submicron and submillimeter emission from the disk. We interpret this as interstellar UV radiation providing an additional source of heating to the outer part of the disk.

Aims. We aim to study vertical settling and radial drift of dust in protoplanetary disks from a different perspective: an edge-on view. An estimation of the amplitude of settling and drift is highly relevant to understanding planet formation. Methods. We analyze a sample of 12 HST-selected edge-on protoplanetary disks (i.e., seen with high inclinations) for which the vertical extent of the emission layers can be constrained directly. We present ALMA high angular resolution continuum images (~0.1′′) of these disks at two wavelengths, 0.89 and 2.06 mm (respectively ALMA bands 7 and 4), supplemented with archival band 6 data (1.33 mm) where available. Results. Several sources show constant brightness profiles along their major axis with a steep drop at the outer edges. Two disks have central holes with additional compact continuum emission at the location of the central star. For most sources, the millimeter continuum emission is more compact than the scattered light, both in the vertical and radial directions. Six sources are resolved along their minor axis in at least one millimetric band, providing direct information on the vertical distribution of the millimeter grains. For the second largest disk of the sample, Tau 042021, the significant difference in vertical extent between band 7 and band 4 suggests efficient size-selective vertical settling of large grains. Furthermore, the only Class I object in our sample shows evidence of flaring in the millimeter. Along the major axis, all disks are well resolved. Four of them are larger in band 7 than in band 4 in the radial direction, and three have a similar radial extent in all bands. These three disks are also the ones with the sharpest apparent edges (between 80% and 20% of the peak flux, Δr∕r ~ 0.3), and two of them are binaries. For all disks, we also derive the millimeter brightness temperature and spectral index maps. We find that all edge-on disks in our sample are likely optically thick and that the dust emission reveals low brightness temperatures in most cases (brightness temperatures ≤10 K). The integrated spectral indices are similar to those of disks at lower inclination. Conclusions. The comparison of a generic radiative transfer disk model with our data shows that at least three disks are consistent with a small millimeter dust scale height, of a few au (measured at r = 100 au). This is in contrast with the more classical value of hg ~ 10 au derived from scattered light images and from gas line measurements. These results confirm, by direct observations, that large (millimeter) grains are subject to significant vertical settling in protoplanetary disks.

Aims. We aim to study vertical settling and radial drift of dust in protoplanetary disks from a different perspective: an edge-on view. An estimation of the amplitude of settling and drift is highly relevant to understanding planet formation. Methods. We analyze a sample of 12 HST-selected edge-on protoplanetary disks (i.e., seen with high inclinations) for which the vertical extent of the emission layers can be constrained directly. We present ALMA high angular resolution continuum images (similar to 0.1 '') of these disks at two wavelengths, 0.89 and 2.06 mm (respectively ALMA bands 7 and 4), supplemented with archival band 6 data (1.33 mm) where available. Results. Several sources show constant brightness profiles along their major axis with a steep drop at the outer edges. Two disks have central holes with additional compact continuum emission at the location of the central star. For most sources, the millimeter continuum emission is more compact than the scattered light, both in the vertical and radial directions. Six sources are resolved along their minor axis in at least one millimetric band, providing direct information on the vertical distribution of the millimeter grains. For the second largest disk of the sample, Tau 042021, the significant difference in vertical extent between band 7 and band 4 suggests efficient size-selective vertical settling of large grains. Furthermore, the only Class I object in our sample shows evidence of flaring in the millimeter. Along the major axis, all disks are well resolved. Four of them are larger in band 7 than in band 4 in the radial direction, and three have a similar radial extent in all bands. These three disks are also the ones with the sharpest apparent edges (between 80% and 20% of the peak flux, Delta r/r similar to 0.3), and two of them are binaries. For all disks, we also derive the millimeter brightness temperature and spectral index maps. We find that all edge-on disks in our sample are likely optically thick and that the dust emission reveals low brightness temperatures in most cases (brightness temperatures <= 10 K). The integrated spectral indices are similar to those of disks at lower inclination. Conclusions. The comparison of a generic radiative transfer disk model with our data shows that at least three disks are consistent with a small millimeter dust scale height, of a few au (measured at r = 100 au). This is in contrast with the more classical value of h(g) similar to 10 au derived from scattered light images and from gas line measurements. These results confirm, by direct observations, that large (millimeter) grains are subject to significant vertical settling in protoplanetary disks.

BACKGROUND Tuberculosis (TB) diagnosis in human immunodeficiency virus (HIV) positive persons is difficult, particularly in resource-limited settings. The relationship between TB culture status and mortality in HIV-positive persons treated for TB is unclear. METHODS We evaluated HIV-positive adults treated for TB at or after their first HIV clinic visit in Argentina, Brazil, Chile, Honduras, Mexico or Peru from 2000 to 2015. Anti-tuberculosis treatment included 2 months of isoniazid, rifampicin (RMP)/rifabutin (RBT), pyrazinamide ± ethambutol, followed by continuation phase treatment with isoniazid + RMP/RBT. RESULTS Of 759 TB-HIV patients, 238 (31%) were culture-negative, 228 (30%) had unknown culture status or did not undergo culture and 293 (39%) were culture-positive. The median CD4 at TB diagnosis was 96 (interquartile range 40-228); 636 (84%) received concurrent antiretroviral therapy (ART) and anti-tuberculosis treatment. There were 123 (16%) deaths: 90/466 (19%) with TB culture-negative, unknown or not performed vs. 33/293 (11%) who were TB culture-positive (P = 0.005). In Kaplan-Meier analysis, mortality in TB patients without culture-confirmed disease was higher (P = 0.002). In a Cox model adjusted for age, sex, CD4, ART timing, disease site and stratified by study site, mortality in persons without culture-confirmed TB was not significantly increased compared to those with culture-positive TB (hazard ratio 1.39, 95%CI 0.89-2.16, P = 0.15). CONCLUSION Most HIV-positive patients treated for TB did not have culture-confirmed TB, and mortality tended to be higher in patients without culture-confirmed disease, although the association was not statistically different after adjusting for other variables. Accurate TB diagnosis in HIV-positive persons is crucial.

We aimed to quantify the proportion of people receiving care for HIV-infection that are 50 years or older (older HIV patients) in Latin America and the Caribbean between 2000 and 2015 and to estimate the contribution to the growth of this population of people enrolled before (<50yo) and after 50 years old (yo) (⩾50yo). We used a series of repeated, cross-sectional measurements over time in the Caribbean, Central and South American network (CCASAnet) cohort. We estimated the percentage of patients retained in care each year that were older HIV patients. For every calendar year, we divided patients into two groups: those who enrolled before age 50 and after age 50. We used logistic regression models to estimate the change in the proportion of older HIV patients between 2000 and 2015. The percentage of CCASAnet HIV patients over 50 years had a threefold increase (8% to 24%) between 2000 and 2015. Most of the growth of this population can be explained by the increasing proportion of people that enrolled before 50 years and aged in care. These changes will impact needs of care for people living with HIV, due to multiple comorbidities and high risk of disability associated with aging.

Background: Cryptococcal meningitis (CM) is associated with substantial mortality in HIV-infected patients. Optimal timing of antiretroviral therapy (ART) in persons with CM represents a clinical challenge, and the burden of CM in Latin America has not been well described. Studies suggest that early ART initiation is associated with higher mortality, but data from the Americas are scarce. Methods: HIV-infected adults in care between 1985–2014 at participating sites in the Latin America (the Caribbean, Central and South America network (CCASAnet)) and the Vanderbilt Comprehensive Care Clinic (VCCC) and who had CM were included. Survival probabilities were estimated. Risk of death when initiating ART within the first 2 weeks after CM diagnosis versus initiating between 2–8 weeks was assessed using dynamic marginal structural models adjusting for site, age, sex, year of CM, CD4 count, and route of HIV transmission. Findings: 340 patients were included (Argentina 58, Brazil 138, Chile 28, Honduras 27, Mexico 34, VCCC 55) and 142 (42%) died during the observation period. Among 151 patients with CM prior to ART 56 (37%) patients died compared to 86 (45%) of 189 with CM after ART initiation (p = 0.14). Patients diagnosed with CM after ART had a higher risk of death (p = 0.03, log-rank test). The probability of survival was not statistically different between patients who started ART within 2 weeks of CM (7/24, 29%) vs. those initiating between 2-8 weeks (14/53, 26%) (p = 0.96), potentially due to lack of power. Interpretation: In this large Latin-American cohort, patients with CM had very high mortality rates, especially those diagnosed after ART initiation. This study reflects the overwhelming burden of CM in HIV-infected patients in Latin America.

We report the discovery of a low-mass companion to HR 3549, an A0V star surrounded by a debris disk with a warm excess detected by WISE at 22 mu m (10 sigma significance). We imaged HR 3549 B in the L band with NAOS-CONICA, the adaptive optics infrared camera of the Very Large Telescope, in January 2013 and confirmed its common proper motion in 2015 January. The companion is at a projected separation of similar or equal to 80 AU and position angle of similar or equal to 157 degrees, so it is orbiting well beyond the warm disk inner edge of r > 10 AU. Our age estimate for this system corresponds to a companion mass in the range 15-80 M-J, spanning the brown dwarf regime, and so HR 3549 B is another recent addition to the growing list of brown dwarf desert objects with extreme mass ratios. The simultaneous presence of a warm disk and a brown dwarf around HR 3549 provides interesting empirical constraints on models of the formation of substellar companions.

AbstractWe present new high-resolution observations and modeling of SSTtau J042021+ 281349, a 400 AU-radius edge-on protoplanetary disk. We have gathered visible and near-infrared scattered light images of the system with the Hubble Space Telescope and Keck adaptive optics system, as well as a 1.3 mm continuum map with CARMA. Compared to the well-known HH 30 disk, this new system is remarkable because of its spectacular bipolar jet and the high degree of lateral symmetry of the disk. Indeed, we argue that this system is a “cleaner” prototype for edge-on disks. In addition, the apparent achromaticity of dust properties (most notably the almost grey opacity law) from the visible to the near-infrared in this disk suggests that it is in an advanced stage of dust evolution.

AbstractWe present detailed models of the edge-on protoplanetary disk ESO Hα 569 (SSTgbs J111110.7-764157) from resolved scattered light images from HST and a complete spectral energy distribution. Data was obtained as part of an HST campaign to catalogue edge-on disks around young stars in nearby star forming regions (HST program 12514, PI: Karl Stapelfeldt). We confirm that this object is an optically thick edge-on disk around a young star with an outer radius of 125 AU. Using full radiative transfer models, we probe the distribution of dust grains and overall shape of the disk (inclination, scale height, dust mass, maximum particle size, inner radius, flaring exponent and surface/volume density exponent).

We present a census of the disc population for UKIDSS selected brown dwarfs in the 510 Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour-magnitude and colour-colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19 per cent) lack excess at 3.4 and 4.6 mu m and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars. We estimate that the time-scale for a typical transition from class II to class III is less than 0.4 Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5-10 Myr and a disc clearing time-scale significantly shorter than 1 Myr.

We report the discovery of the first new ultra-cool brown dwarf found with the Wide-field Infrared Survey Explorer (WISE). The object's preliminary designation is WISEPC J045853.90+643451.9. Follow-up spectroscopy with the LUCIFER instrument on the Large Binocular Telescope indicates that it is a very late-type T dwarf with a spectral type approximately equal to T9. Fits to an IRTF/SpeX 0.8-2.5 micron spectrum to the model atmospheres of Marley and Saumon indicate an effective temperature of approximately 600 K as well as the presence of vertical mixing in its atmosphere. The new brown dwarf is easily detected by WISE, with a signal-to-noise ratio of ~36 at 4.6 microns. Current estimates place it at a distance of 6 to 10 pc. This object represents the first in what will likely be hundreds of nearby brown dwarfs found by WISE that will be suitable for follow up observations, including those with the James Webb Space Telescope. One of the two primary scientific goals of the WISE mission is to find the coolest, closest stars to our Sun; the discovery of this new brown dwarf proves that WISE is capable of fulfilling this objective.

We have carried out a survey of the north and south ecliptic poles, EP-N and EP-S, respectively, with the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE). The primary objective was to cross-calibrate WISE with the Spitzer and Midcourse Space Experiment (MSX) photometric systems by developing a set of calibration stars that are common to these infrared missions. The ecliptic poles were continuous viewing zones for WISE due to its polar-crossing orbit, making these areas ideal for both absolute and internal calibrations. The Spitzer IRAC and MIPS imaging survey covers a complete area of 0.40 deg(2) for the EP-N and 1.28 deg(2) for the EP-S. WISE observed the whole sky in four mid-infrared bands, 3.4, 4.6, 12, and 22 mu m, during its eight-month cryogenic mission, including several hundred ecliptic polar passages; here we report on the highest coverage depths achieved by WISE, an area of similar to 1.5 deg(2) for both poles. Located close to the center of the EP-N, the Sy-2 galaxy NGC 6552 conveniently functions as a standard calibrator to measure the red response of the 22 mu m channel of WISE. Observations from Spitzer-IRAC/MIPS/IRS-LL and WISE show that the galaxy has a strong red color in the mid-infrared due to star-formation and the presence of an active galactic nucleus (AGN), while over a baseline >1 year the mid-IR photometry of NGC 6552 is shown to vary at a level less than 2%. Combining NGC 6552 with the standard calibrator stars, the achieved photometric accuracy of the WISE calibration, relative to the Spitzer and MSX systems, is 2.4%, 2.8%, 4.5%, and 5.7% for W1 (3.4 mu m), W2 (4.6 mu m), W3 (12 mu m), and W4 (22 mu m), respectively. The WISE photometry is internally stable to better than 0.1% over the cryogenic lifetime of the mission. The secondary objective of the Spitzer-WISE Survey was to explore the poles at greater flux-level depths, exploiting the higher angular resolution Spitzer observations and the exceptionally deep (in total coverage) WISE observations that potentially reach down to the confusion limit of the survey. The rich Spitzer and WISE data sets were used to study the Galactic and extragalactic populations through source counts, color-magnitude and color-color diagrams. As an example of what the data sets facilitate, we have separated stars from galaxies, delineated normal galaxies from power-law-dominated AGNs, and reported on the different fractions of extragalactic populations. In the EP-N, we find an AGN source density of similar to 260 deg(-2) to a 12 mu m depth of 115 mu Jy, representing 15% of the total extragalactic population to this depth, similar to what has been observed for low-luminosity AGNs in other fields.

We use the Spitzer Wide-area InfraRed Extragalactic Legacy Survey (SWIRE) to explore the specific star formation activity of galaxies and their evolution near the peak of the cosmic far-infrared (FIR) background at 70 and 160 mu m. We use a stacking analysis to determine the mean FIR properties of well-defined subsets of galaxies at flux levels well below the FIR catalogue detection limits of SWIRE and other Spitzer surveys. We tabulate the contribution of different subsets of galaxies to the FIR background at 70 and 160 mu m. These long wavelengths provide a good constraint on the bolometric obscured emission. The large area provides good constraints at low z and in finer redshift bins than previous work. At all redshifts we find that the specific FIR luminosity decreases with increasing mass, following a trend L-FIR/M-* proportional to M beta(*) with beta = -0.38 +/- 0.14. This is a more continuous change than expected from the De Lucia & Blaizot semi-analytic model suggesting modifications to the feedback prescriptions. We see an increase in the specific FIR luminosity by about a factor of similar to 100 from 0 < z < 2 and find that the specific FIR luminosity evolves as (1 + z)alpha with alpha = 4.4 +/- 0.3 for galaxies with 10.5 < log(10) M-*/M-circle dot < 12. This is considerably steeper than the De Lucia & Blaizot semi-analytic model (alpha similar to 2.5). When separating galaxies into early and late types on the basis of the optical/IR spectral energy distributions we find that the decrease in specific FIR luminosity with stellar mass is stronger in early-type galaxies (beta similar to -0.46), while late-type galaxies exhibit a flatter trend (beta similar to -0.15). The evolution is strong for both classes but stronger for the early-type galaxies. The early types show a trend of decreasing strength of evolution as we move from lower to higher masses while the evolution of the late-type galaxies has little dependence on stellar mass. We suggest that in late-type galaxies we are seeing a consistently declining specific star formation rate alpha = 3.36 +/- 0.16 through a common phenomenon, for example, exhaustion of gas supply, i.e. not systematically dependent on the local properties of the galaxy.

Aims. The brown dwarf (BD) formation process has not yet been completely understood. To shed more light on the differences and similarities between star and BD formation processes, we study and compare the disk fraction among both kinds of objects over a large angular region in the Taurus cloud. In addition, we examine the spatial distribution of stars and BD relative to the underlying molecular gas. Methods. In this paper, we present new and updated photometry data from the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope on 43 BDs in the Taurus cloud, and recalculate of the BD disk fraction in this region. We also useed recently available CO mm data to study the spatial distribution of stars and BDs relative to the cloud's molecular gas. Results. We find that the disk fraction among BDs in the Taurus cloud is 41 ± 12%, a value statistically consistent with the one among TTS (58 ± 9%). We find that BDs in transition from a state where they have a disk to a diskless state are rare, and we study one isolated example of a transitional disk with an inner radius of ≈0.1 AU (CFHT BD Tau 12, found via its relatively small mid-IR excess compared to most members of Taurus that have disks. We find that BDs are statistically found in regions of similar molecular gas surface density to those associated with stars. Furthermore, we find that the gas column density distribution is almost identical for stellar and substellar objects with and without disks.