Microlensing events in the Galactic bulge

For the first time we detected microlensing events at zero latitude in the Galactic bulge using the VISTA Variables in the Via Lactea Survey (VVV) data. We have discovered a total sample of N = 630 events within an area covering 20.7 sq. deg. Using the near-IR color magnitude diagram we selected N = 291 red clump sources, allowing us to analyse the longitude dependence of microlensing across the central region of the Galactic plane. We thoroughly accounted for the photometric and sampling efficiency. The spatial distribution is homogeneous, with the number of events smoothly increasing toward the Galactic center. We find a slight asymmetry, with a larger number of events toward negative longitudes than positive longitudes, that is possibly related with the inclination of the bar along the line of sight. We also examined the timescale distribution which shows a mean on 17.4 +- 1.0 days for the whole sample, and 20.7 +- 1.0 for the Red Clump subsample.Comment: Proceedings of the Fifteenth Marcel Grossman Meeting on General Relativity Edited by Elia Battistelli, Robert T. Jantzen, and Remo Ruffini. 6 pages, 3 figures, to be published in Open access e-book proceedings World Scientific, Singapore, 201

VVV Survey Microlensing : Catalog of Best and Forsaken Events

© 2020. The American Astronomical Society. All rights reserved.We search for microlensing events in the zero-latitude area of the Galactic Bulge using the VVV Survey near-IR data. We have discovered a total sample of N = 630 events within an area covering 20.68 deg 2 between the years 2010 and 2015. In this paper, we describe the search and present the data for the final sample, including near-IR magnitudes, colors, and proper motions, as well as the standard microlensing parameters. We use the near-IR color-magnitude and color-color diagrams to select N RC = 290 events with red-clump sources to analyze the extinction properties of the sample in the central region of the Galactic plane. The timescale distribution and its dependence in the longitude axis is presented. The mean timescale decreases as we approach the Galactic minor axis (b = 0ˆ). Finally, we give examples of special microlensing events, such as binaries, short-timescale events, and events with a strong parallax effect.Peer reviewe

Milky Way demographics with the VVV survey. IV. PSF photometry from almost one billion stars in the Galactic bulge and adjacent southern disk

Accepted for publication in a forthcoming issue of Astronomy & Astrophysics. Reproduced with permission from Astronomy & Astrophysics. © 2018 ESO.Context. The inner regions of the Galaxy are severely affected by extinction, which limits our capability to study the stellar populations present there. The Vista Variables in the Vía Láctea (VVV) ESO Public Survey has observed this zone at near-infrared wavelengths where reddening is highly diminished. Aims. By exploiting the high resolution and wide field-of-view of the VVV images we aim to produce a deep, homogeneous, and highly complete database of sources that cover the innermost regions of our Galaxy. Methods. To better deal with the high crowding in the surveyed areas, we have used point spread function (PSF)-fitting techniques to obtain a new photometry of the VVV images, in the ZY JHK s near-infrared filters available. Results. Our final catalogs contain close to one billion sources, with precise photometry in up to five near-infrared filters, and they are already being used to provide an unprecedented view of the inner Galactic stellar populations. We make these catalogs publicly available to the community. Our catalogs allow us to build the VVV giga-CMD, a series of color-magnitude diagrams of the inner regions of the Milky Way presented as supplementary videos. We provide a qualitative analysis of some representative CMDs of the inner regions of the Galaxy, and briefly mention some of the studies we have developed with this new dataset so far.Peer reviewe

Confirmation of a New Metal-poor Globular Cluster in the Galactic Bulge

© 2018. The American Astronomical Society. All rights reserved.We use deep near-IR photometry of the VISTA Variables in the V'a L'ctea (VVV) Survey and deep DECam Plane Survey (DECaPS) optical photometry to confirm the physical reality of the candidate globular cluster (GC) Minni 22, which is located in the Galactic bulge. This object, which was detected as a high density region in our maps of bulge red giants, is now confirmed as a real GC based on the optical and near-IR color'magnitude diagrams. We also recover three known fundamental mode (ab type) RR Lyrae stars within 2 arcmin of the cluster center. The presence of RR Lyrae stars also seems to confirm Minni 22 as a bonafide old and metal-poor GC. We estimate a cluster reddening E(J - Ks) = 0.6 mag and determine its heliocentric distance D = 7.4 ± 0.3 kpc. The optical and near-IR color'magnitude diagrams reveal well-defined red giant branches in all cases, including a red giant branch bump at Ks = 13.30 ± 0.05 mag. The comparison with theoretical isochrones yields a mean metallicity of [Fe/H] = -1.3 ± 0.3 dex, and age of t ∼ 11.2 Gyr. This is a good example of a new low-luminosity (MV = -6.2 mag) GC found in the central bulge of the Milky Way. After discussing the different ways to confirm the existence of bulge GC candidates, we find that one of the best methods is to use the CMDs from the combination of the DECaPS + VVV photometries.Peer reviewe

Household Hardships, Public Programs, and Their Associations with the Health and Development of Very Young Children: Insights from Children’s HealthWatch

America’s low-income families struggle to protect their children from multiple threats to their health and growth. Many research and advocacy groups explore the health and educational effects of food insecurity, but less is known about these effects on very young children. Children’s HealthWatch, a group of pediatric clinicians and public health researchers, has continuously collected data on the effects of food insecurity alone and in conjunction with other household hardships since 1998. The group’s peer reviewed research has shown that a number of economic risks at the household level, including food, housing and energy insecurity, tend to be correlated. These insecurities alone or in conjunction increase the risk that a young child will suffer various negative health consequences, including increases in lifetime hospitalizations, parental report of fair or poor health,1 or risk for developmental delays.2 Child food insecurity is an incremental risk indicator above and beyond the risk imposed by household-level food insecurity. The Children’sHealthwatch research also suggests public benefits programs modify some of these effects for families experiencing hardships. This empirical evidence is presented in a variety of public venues outside the usual scientific settings, such as congressional hearings, to support the needs of America’s most vulnerable population through policy change. Children’s HealthWatch research supports legislative solutions to food insecurity, including sustained funding for public programs and re-evaluation of the use of the Thrifty Food Plan as the basis of SNAP benefits calculations. Children’s HealthWatch is one of many models to support the American Academy of Pediatrics’ call to “stand up, speak up, and step up for children.”3 No isolated group or single intervention will solve child poverty or multiple hardships. However, working collaboratively each group has a role to play in supporting the health and well-being of young children and their families. 1. Cook JT, Frank DA, Berkowitz C, et al. Food insecurity is associated with adverse health outcomes among human infants and toddlers. J Nutr. 2004;134:1432-1438. 2. Rose-Jacobs R, Black MM, Casey PH, et al. Household food insecurity: associations with at-risk infant and toddler development. Pediatrics. 2008;121:65-72. 3. AAP leader says to stand up, speak up, and step up for child health [news release]. Boston, MA: American Academy of Pediatrics; October 11, 2008. http://www2.aap.org/pressroom/nce/nce08childhealth.htm. Accessed January 1, 2012

Fifty star cluster candidates towards the Galactic bulge from VVV and Gaia

We have extended our previous bulge GC searches following the procedures described by Minniti et al. (2017abc), adding a couple of additional steps to target more distant objects. Considering the high foreground contamination and in order to discard nearby sources, we used the matched VVV-Gaia catalogues of Kammers et al. (2019), with distances DBJ < 3 kpc (Bailer Jones 2018). Also, we rejected sources with proper motions consistent with the mean motion of the Galactic disk for the different fields. We then built red giant density maps and identified the over-densities with sizes typical for GCs. Finally, we checked the optical and near-IR color-magnitude diagrams for all individual objects, selecting the ones with red giant branches tighter than their surrounding fields. While in most targets a clear red clump is present, in a few cases there is also a concentration of RR Lyrae stars and/or a blue horizontal branch can be observed. We found fifty new candidate GCs.Fil: Minniti, Dante. Universidad Andrés Bello; ChileFil: Alonso-Garcia, Javier. Universidad de Antofagasta; ChileFil: Borissova, Jura. Universidad de Valparaíso; ChileFil: Claria Olmedo, Juan Jose. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Días, Bruno. Universidad Andrés Bello; ChileFil: Gómez, Matias. Universidad Andrés Bello; ChileFil: Hempel, Maren. Universidad Andrés Bello; ChileFil: Kurtev, Radostin. Universidad de Valparaíso; ChileFil: Palma, Tali. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pullen, Joyce. Universidad Andrés Bello; ChileFil: Saito, Roberto K. Universidade Federal de Santa Catarina; Brasi

New VVV Survey Globular Cluster Candidates in the Milky Way Bulge

© 2017 The American Astronomical Society. All rights reserved.It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color-magnitude diagrams. We provide their coordinates as well as their near-IR color-magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color-magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A Ks < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color-magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.Peer reviewedFinal Accepted Versio

FSR 1716: A New Milky Way Globular Cluster Confirmed Using VVV RR Lyrae Stars

Published version.We use deep multi-epoch near-IR images of the VISTA Variables in the Vía Láctea (VVV) Survey to search for RR Lyrae stars toward the Southern Galactic plane. Here, we report the discovery of a group of RR Lyrae stars close together in VVV tile d025. Inspection of the VVV images and PSF photometry reveals that most of these stars are likely to belong to a globular cluster that matches the position of the previously known star cluster FSR 1716. The stellar density map of the field yields a >100 detection for this candidate globular cluster that is centered at equatorial coordinates R.A.J2000 = 16:10:30.0, decl.J2000 = −53:44:56 and galactic coordinates l = 329.77812, b = −1.59227. The color-magnitude diagram of this object reveals a well-populated red giant branch, with a prominent red clump at Ks = 13.35 0.05, and J − Ks = 1.30 0.05. We present the cluster RR Lyrae positions, magnitudes, colors, periods, and amplitudes. The presence of RR Lyrae indicates an old globular cluster, with an age >10 Gyr. We classify this object as an Oosterhoff type I globular cluster, based on the mean period of its RR Lyrae type ab, days, and argue that this is a relatively metal-poor cluster with [Fe/H] = −1.5 0.4 dex. The mean extinction and reddening for this cluster are and E(J − Ks) = 0.72 0.02 mag, respectively, as measured from the RR Lyrae colors and the near-IR color-magnitude diagram. We also measure the cluster distance using the RR Lyrae type ab stars. The cluster mean distance modulus is (m − M)0 = 14.38 0.03 mag, implying a distance D = 7.5 0.2 kpc and a Galactocentric distance RG = 4.3 kpc

Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane

Published version.Deep near-IR images from the VISTA Variables in the Vía Láctea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a thin slice of the fourth Galactic quadrant (295° < < 350°, −2 24 < b < −1 05). The sample's distance distribution exhibits a maximum density that occurs at the bulge tangent point, which implies that this primarily Oosterhoff type I population of RRab stars does not trace the bar delineated by their red clump counterparts. The bulge RR Lyrae population does not extend beyond ∼ 340°, and the sample's spatial distribution presents evidence of density enhancements and substructure that warrants further investigation. Indeed, the sample may be employed to evaluate Galactic evolution models, and is particularly lucrative since half of the discovered RR Lyrae are within reach of Gaia astrometric observations

Development and validation of an ultra?performance liquid chromatography quadrupole time of flight mass spectrometry method for rapid quantification of free amino acids in human urine

An ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-qTOFMS)method using hydrophilic interaction liquid chromatography was developed and validated for simultaneous quantification of 18 free amino acids in urine with a total acquisition time including the column re-equilibration of less than 18 min per sample. This method involves simple sample preparation steps which consisted of 15 times dilution with acetonitrile to give a final composition of 25 % aqueous and 75 % acetonitrile without the need of any derivatization. The dynamic range for our calibration curve is approximately two orders of magnitude (120-fold from the lowest calibration curve point) with good linearity (r2 ? 0.995 for all amino acids). Good separation of all amino acids as well as good intra- and inter-day accuracy (<15 %) and precision (<15 %) were observed using three quality control samples at a concentration of low, medium and high range of the calibration curve. The limits of detection (LOD) and lower limit of quantification of our method were ranging from approximately 1–300 nM and 0.01–0.5 µM, respectively. The stability of amino acids in the prepared urine samples was found to be stable for 72 h at 4 °C, after one freeze thaw cycle and for up to 4 weeks at ?80 °C. We have applied this method to quantify the content of 18 free amino acids in 646 urine samples from a dietary intervention study. We were able to quantify all 18 free amino acids in these urine samples, if they were present at a level above the LOD. We found our method to be reproducible (accuracy and precision were typically <10 % for QCL, QCM and QCH) and the relatively high sample throughput nature of this method potentially makes it a suitable alternative for the analysis of urine samples in clinical setting