A Next Generation High-speed Data Acquisition System for Multi-channel Infrared and Optical Photometry

We report the design, operation, and performance of a next generation high-speed data acquisition system for multi-channel infrared and optical photometry based on the modern technologies of Field Programmable Gate Arrays, the Peripheral Component Interconnect bus, and the Global Positioning System. This system allows either direct recording of photon arrival times or binned photon counting with time resolution up to 1-$\mu$s precision in Universal Time, as well as real-time data monitoring and analysis. The system also allows simultaneous recording of multi-channel observations with very flexible, reconfigurable observational modes. We present successful 20-$\mu$s resolution simultaneous observations of the Crab Nebula Pulsar in the infrared (H-band) and optical (V-band) wavebands obtained with this system and 100-$\mu$s resolution V-band observations of the dwarf nova IY Uma with the 5-m Hale telescope at the Palomar Observatory.Comment: 11 pages, including 4 figures, to appear in PAS

Exploring a New Population of Compact Objects: X-ray and IR Observations of the Galactic Centre

I describe the IR and X-ray observational campaign we have undertaken for the purpose of determining the nature of the faint discrete X-ray source population discovered by Chandra in the Galactic Center (GC). Data obtained for this project includes a deep Chandra survey of the Galactic Bulge; deep, high resolution IR imaging from VLT/ISAAC, CTIO/ISPI, and the UKIDSS Galactic Plane Survey (GPS); and IR spectroscopy from VLT/ISAAC and IRTF/SpeX. By cross-correlating the GC X-ray imaging from Chandra with our IR surveys, we identify candidate counterparts to the X-ray sources via astrometry. Using a detailed IR extinction map, we are deriving magnitudes and colors for all the candidates. Having thus established a target list, we will use the multi-object IR spectrograph FLAMINGOS-2 on Gemini-South to carry out a spectroscopic survey of the candidate counterparts, to search for emission line signatures which are a hallmark of accreting binaries. By determining the nature of these X-ray sources, this FLAMINGOS-2 Galactic Center Survey will have a dramatic impact on our knowledge of the Galactic accreting binary population.Comment: 4 pages, 2 figures, to appear in the Proceedings of The Second Kolkata Conference on Observational Evidence for Black Holes in the Universe'', ed. S. Charkrabarti, Kolkata, India; AIP Conf. Serie

The Wide Integral Field Infrared Spectrograph: Commissioning Results and On-sky Performance

We have recently commissioned a novel infrared ($0.9-1.7$ $\mu$m) integral field spectrograph (IFS) called the Wide Integral Field Infrared Spectrograph (WIFIS). WIFIS is a unique instrument that offers a very large field-of-view (50$^{\prime\prime}$ x 20$^{\prime\prime}$) on the 2.3-meter Bok telescope at Kitt Peak, USA for seeing-limited observations at moderate spectral resolving power. The measured spatial sampling scale is $\sim1\times1^{\prime\prime}$ and its spectral resolving power is $R\sim2,500$ and $3,000$ in the $zJ$ ($0.9-1.35$ $\mu$m) and $H_{short}$ ($1.5-1.7$ $\mu$m) modes, respectively. WIFIS's corresponding etendue is larger than existing near-infrared (NIR) IFSes, which are mostly designed to work with adaptive optics systems and therefore have very narrow fields. For this reason, this instrument is specifically suited for studying very extended objects in the near-infrared such as supernovae remnants, galactic star forming regions, and nearby galaxies, which are not easily accessible by other NIR IFSes. This enables scientific programs that were not originally possible, such as detailed surveys of a large number of nearby galaxies or a full accounting of nucleosynthetic yields of Milky Way supernova remnants. WIFIS is also designed to be easily adaptable to be used with larger telescopes. In this paper, we report on the overall performance characteristics of the instrument, which were measured during our commissioning runs in the second half of 2017. We present measurements of spectral resolving power, image quality, instrumental background, and overall efficiency and sensitivity of WIFIS and compare them with our design expectations. Finally, we present a few example observations that demonstrate WIFIS's full capability to carry out infrared imaging spectroscopy of extended objects, which is enabled by our custom data reduction pipeline.Comment: Published in the Proceedings of SPIE Astronomical Telescopes and Instrumentation 2018. 17 pages, 13 figure

Feedback Control Methods on Short-Period Orbits Of the Earth-Moon Equilateral Libration Points

Recent research by the authors suggests a unique approach to perform Lunar occultations for a diverse set of scientific applications. Under the circular restricted three-body problem assumptions, short-period orbits (SPOs) near the Earth-Moon equilateral Libration points have been suggested for optimal eclipse time and minimal fuel consumption requirements to stay in orbit. Nevertheless, under the presence of orbital perturbations, SPOs are no longer stable as gravitational effects from neighboring celestial bodies continuously perturb these orbits. In this sense, the current study compares a wide range of control methods, including Lyapunov-based adaptive control schemes and fuel-optimal control policies, to address the fuel consumption and tracking issues of the perturbed system. This inquiry attests that perturbations are effectively cancelled out to achieve the proposed scientific objectives with minimal station-keeping requirements

A Binary Millisecond Pulsar in Globular Cluster NGC6544

We report the detection of a new 3.06 ms binary pulsar in the globular cluster NGC6544 using a Fourier-domain ``acceleration'' search. With an implied companion mass of ~0.01 solar masses and an orbital period of only P_b~1.7 hours, it displays very similar orbital properties to many pulsars which are eclipsed by their companion winds. The orbital period is the second shortest of known binary pulsars after 47 Tuc R. The measured flux density of 1.3 +/- 0.4 mJy at 1332 MHz indicates that the pulsar is almost certainly the known steep-spectrum point source near the core of NGC6544.Comment: Accepted by ApJ Letters on 11 October 2000, 5 page

Determining the nature of the faint X-ray source population near the Galactic Centre

We present results of a multi-wavelength program to study the faint discrete X-ray source population discovered by Chandra in the Galactic Centre (GC). From IR imaging obtained with the VLT we identify candidate K-band counterparts to 75% of the X-ray sources in our sample. By combining follow-up VLT K-band spectroscopy of a subset of these candidate counterparts with the magnitude limits of our photometric survey, we suggest that only a small percentage of the sources are HMXBs, while the majority are likely to be canonical LMXBs and CVs at the distance of the GC. In addition, we present our discovery of highly structured small-scale (5-15") extinction towards the Galactic Centre. This is the finest-scale extinction study of the Galactic Centre to date. Finally, from these VLT observations we are able to place constraints on the stellar counterpart to the ``bursting pulsar'' GRO J1744-28.Comment: 9 pages, in Proceedings of "VI Microquasar Workshop: Microquasars and Beyond, 18-22 September 2006, Como, Italy; paper in PDF format with full-resolution figures available at http://www.astro.ufl.edu/~reba/mqw_rmb.pd

Radio Astronomy

Contains reports on nine research projects.National Science Foundation (Grant AST 86-17172)National Aeronautics and Space Administration (Contract NAS7-918)Jet Propulsion Laboratory (Contract 958048)U.S. Navy - Office of Naval Research (Contract N00014-84-C-2082)U.S. Navy - Office of Naval Research (Contract N00014-86-C-2114)SM Systems and Research, Inc.National Aeronautics and Space Administration/Goddard Space Flight Center (Grant NAG5-10)Center for Advanced Television StudiesBrazil, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (Grant 300.832-82)National Aeronautics and Space Administration/Goddard Space Flight Center (Grant NAG5-537

On the discovery of stars, quasars, and galaxies in the Southern Hemisphere with S-PLUS DR2

This paper provides a catalogue of stars, quasars, and galaxies for the Southern Photometric Local Universe Survey Data Release 2 (S-PLUS DR2) in the Stripe 82 region. We show that a 12-band filter system (5 Sloan-like and 7 narrow bands) allows better performance for object classification than the usual analysis based solely on broad bands (regardless of infrared information). Moreover, we show that our classification is robust against missing values. Using spectroscopically confirmed sources retrieved from the Sloan Digital Sky Survey DR16 and DR14Q, we train a random forest classifier with the 12 S-PLUS magnitudes + 4 morphological features. A second random forest classifier is trained with the addition of the W1 (3.4 μm) and W2 (4.6 μm) magnitudes from the Wide-field Infrared Survey Explorer (WISE). Forty-four per cent of our catalogue have WISE counterparts and are provided with classification from both models. We achieve 95.76 per cent (52.47 per cent) of quasar purity, 95.88 per cent (92.24 per cent) of quasar completeness, 99.44 per cent (98.17 per cent) of star purity, 98.22 per cent (78.56 per cent) of star completeness, 98.04 per cent (81.39 per cent) of galaxy purity, and 98.8 per cent (85.37 per cent) of galaxy completeness for the first (second) classifier, for which the metrics were calculated on objects with (without) WISE counterpart. A total of 2926 787 objects that are not in our spectroscopic sample were labelled, obtaining 335 956 quasars, 1347 340 stars, and 1243 391 galaxies. From those, 7.4 per cent, 76.0 per cent, and 58.4 per cent were classified with probabilities above 80 per cent. The catalogue with classification and probabilities for Stripe 82 S-PLUS DR2 is available for download. © 2021 The Author(s).This work has been supported by a PhD fellowship to the lead author from Fundacao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP), 2019/01312-2. LN also acknowledges the support of Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brasil (CAPES) -Finance Code 001 and FAPESP through process number 2014/10566-4. LN also thanks the staff of the Astronomy department from the University of Florida, where part of this work was done; Marco Antonio dos Santos and Ulisses Manzo Castello for the technical support; Luis Manrique for the technical support, feedback, and discussions about Machine Learning; Christian Massao Tsujiguchi Takagi and Vin ' icius Amaral Haga for the feedback on the accessibility of the figures in this paper; Gustavo Oliveira Schwarz for building the database. CMdO acknowledges funding from FAPESP through grants 2009/542028 and 2019/26492-3 and funding from the Brazilian National Research Council (CNPq), through grant 309209/2019-6. NSTH acknowledges FAPESP (grants 2017/25835-9 and 2015/22308-2). CQ acknowledges support from FAPESP (grants 2015/11442-0 and 2019/06766-1). AM acknowledges FAPESP scholarship grant 2018/25671-9. CEB acknowledges FAPESP, grant 2016/12331-0. FA-F acknowledges funding for this work from FAPESP grant 2018/20977-2. LSJ acknowledges support from Brazilian agencies FAPESP (2019/10923-5) and CNPq (304819/201794). AAC acknowledges support from Fundacao de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ; grant E26/203.186/2016) and CNPq (grants 304971/2016-2 and 401669/2016-5). EVL acknowledges funding for this work from CNPq grant 169181/2017-0 and CAPES grant 88887.470064/2019-00. MLB acknowledges FAPESP, grants 2018/09165-6 and 2019/23388-0. KMD acknowledges support from FAPERJ (grant E-26/203.184/2017), CNPq (grant 312702/2017-5) and the Serrapilheira Institute (grant Serra-1709-17357). AAC acknowledges support from FAPERJ (grant E26/203.186/2016), CNPq (grants 304971/2016-2 and 401669/2016-5), from the Universidad de Alicante under contract UATALENTO18-02, and from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). ARL acknowledges the financial support from CNPq through the PCI (Programa de Capacitacao Institucional) fellowship. The S-PLUS project, including the T80-South robotic telescope and the S-PLUS scientific survey, was founded as a partnership between FAPESP, the Observatorio Nacional (ON), the Federal University of Sergipe (UFS), and the Federal University of Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena), and Spain (Centro de Estudios de Física del Cosmos de Aragón, CEFCA). We further acknowledge financial support from FAPESP, CNPq, CAPES, FAPERJ, and the Brazilian Innovation Agency (FINEP).Peer reviewe

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the Sloan 2.5 m Telescope, APOGEE has collected a half million high-resolution (R ~ 22,500), high signal-to-noise ratio (>100), infrared (1.51–1.70 μm) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design—hardware, field placement, target selection, operations—and gives an overview of these aspects as well as the data reduction, analysis, and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity, and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12 and later releases, all of the APOGEE data products are publicly available