Observations - November, 2011

Abstracts

ALFALFA: The Arecibo Legacy Fast ALFA Survey (A2010)
PI �?? Dr. Riccardo Giovanelli, Cornell University
Co-PI �?? Dr. Martha Haynes
Proposal Date: September 29, 2004

Abstract: We propose to initiate the Arecibo Legacy Fast ALFA (ALFALFA) Survey, a key element of the E-ALFA Consortium science program. Conducted in a 2-pass fixed-azimuth drift mode sampling 100 MHz with 5 km/s resolution, ALFALFA will survey 7000 square degrees away from the galactic plane, including both the rich central regions of the Local Supercluster and the low density anti-Virgo region. It is specifically designed to explore the very low mass end of the HI mass function in the local universe, the nature of dwarf galaxies and high velocity clouds, the extent and origin of HI disks, and the structure and dynamics of the Local Supercluster. As a wide area legacy survey, ALFALFA will enable a broad range of correlative studies with like datasets such as SDSS, 2MASS and GALEX to quantify environmental variations in the Local and nearby superclusters such as Pisces-Perseus and A1367-Coma. Eight times more sensitive than HIPASS with 4 times the angular resolution, ALFALFA will also provide the first wide area blind survey for HI tidal remnants, low z HI absorbers and OH megamasers in the range 0.16 <z <0.25. Its dataset will also be used in the statistical characterization of continuum transients, and both G-ALFA and P-ALFA programs will be conducted commensally, when multiple backends are available. Top

The Arecibo Galaxy Environments Survey (AGES) (A2048)
PI �?? Dr. Jonathan I Davies, Cardiff University, UK
Proposal Date: January 27, 2006

Abstract: In this Extragalactic ALFA consortium proposal we are requesting 2000 hours of observing time over a 4 year period. The survey is specifically designed to investigate various galactic environments to higher sensitivity with better spatial, and velocity resolution than previous, fully sampled, 21cm multi-beam surveys. We have chosen specific objects in the nearby Universe upon which to centre our observations,Қ but will also use the full depth of the survey to quantify the HI properties of more distant galaxies. Our science goals include: the HI mass function in different environments, the contribution of neutral gas to the baryonic mass density, the nature of and link between high velocity hydrogen clouds and dwarf galaxies, the identification of gaseous tidal features as signatures of galaxy interactions and mergers, the low column density extent of galaxies, a comparison with atomic hydrogen detected by QSO absorption lines, the identification of isolated neutral gas clouds, the spatial distribution and properties of HI-selected galaxies and comparisons with numerical models of galaxy formation. Top

The G-ALFA Continuum Transit Survey (A2130)
PI �?? Dr. Andrew R. Taylor, University of Calgary
Co-PI �?? Dr. Christopher J. Salter
Proposal Date: June 1st, 2005

Abstract: As part of the GALFA consortium we propose to use Arecibo and ALFA to carry out a sensitive, high resolution, spectro-polarimetric survey of the Arecibo sky �?? the GALFA Continuum Transit Survey, GALFACTS. GALFACTS will be a major observational advance in imaging of the polarized radiation from the Milky Way and other galaxies, and promises a transformational advance in our understanding of the magnetic field of the Milky Way, the properties of the magneto-ionic medium, and the role of magnetic fields in galactic processes. We will also explore the polarization properties of a vast number of extragalactic radio sources down to sub-mJy levels. GALFACTS will be a scientific pathfinder to the Square Kilometer Array in the area of cosmic magnetism, and will not be surpassed until the SKA turns on as survey instrument late in the next decade. Top

The Alfa Ultra-Deep Survey: Deep HI Observations at 0<z<0.16 (A2133)
PI �?? Dr. Wolfram Freudling, Space Telescope - European Coordinating Facility
Proposal Date: June 8, 2008

Abstract: The improved spatial and spectral survey capabilities available with ALFA opened a new era of high sensitivity observations for the Arecibo telescope. In a precursor experiment, we have demonstrated that it is possible to achieve noise of less than 50micro-Jy with integration times of about 40 hours per pointing, which translates into a HI mass sensitivity of a few 10E8 Msun at a redshift of about 0.16. We propose to use the new 200 MHz spectrometer available in late 2005 to carry out a blind HI survey with unprecedented sensitivity of 50micro-Jy for the redshift range of 0<z<0.16 over a total area of 0.36 square degrees. The "ALFA Ultra Deep Survey" (AUDS) survey is more than an order of magnitude more sensitive than other HI surveys currently being carried out at Arecibo. The main scientific goals of the survey are to investigate the evolution of HI gas in the universe and explore the low-density gas around the edges of galaxies. The survey will be the deepest "blind" HI survey ever conducted. It will provide for the first time a direct link between HI absorption line measurements at high and intermediate redshifts and 21-cm emission line measurements at low redshifts. The expected number of HI detections at z>0.1 will be larger than that of all previous targeted and blind surveys combined. Top

Discovering Milky Way HII Regions (A2500)
PI �?? Dr. Thomas M. Bania, Boston University Astronomy Department
Co-PI �?? Dr. Dana Balser
Proposal Date: May 22nd, 2009

Abstract: We are finding a large population of previously unknown Galactic HII regions using the GBT at X-band to discover recombination line (RRL) emission from these nebulae. Here we seek to extend our discovery survey by using the superior sensitivity of Arecibo to find nebulae that are too weak and too small to be detected by the GBT. Since HII region RRLs are optically thin at X-band we can discover HII regions across the entire Galactic disk. We can get a complete census of all nebulae ionized by single O-type stars in the survey zone. We will determine the nebular kinematic distances, luminosities, metallicities (via the electron temperature, Te) and helium abundances (4He/H=Y). Both Te and Y provide important constraints on models for Galactic chemical evolution, GCE, and about 10% of these new nebulae will be located in the GCE-critical region beyond the Solar orbit. Top

Densitometry of star-forming dusty clumps throughout the Galaxy (A2584)
PI �?? Dr. Adam Ginsburg, University of Colorado, Boulder
Co-PI �?? Dr. Jeremy Darling
Proposal Date: June 1st, 2010

Abstract: We propose to obtain measurements of the dense mass fraction of young star-forming complexes in a variety of Galactic environments using beam-matched formaldehyde absorption line observations on the GBT at 2 cm and Arecibo at 6 cm. The pilot program GBT09C-049, combined with archival Arecibo data, demonstrated the possibility of efficiently measuring dense gas mass fractions in Galactic molecular clumps with the GBT and Arecibo. We propose to expand that initial sample of 22 ultracompact HII regions to 409 clumps in a wide range of evolutionary states, including inactive and star-forming infrared dark clouds, HII regions, and filamentary structures. We will use formaldehyde densitometry to measure the density and dense gas mass fraction in these 409 clumps. These measurements will be used to track the evolutionary path of molecular clumps intermediate between giant molecular clouds and protostellar cores, and the large sample size will allow us to estimate the relative lifetimes of each state. The GBT observations have already been approved, but completion of this project depends critically on the Arecibo data. Top

Mapping the Cold Local Ribbon (A2587)
PI �?? Dr. Joshua E. Peek, Columbia University
Proposal Date: June 1st, 2011

Abstract: We have mapped a very cold local cloud using Arecibo, and we wish to extend these observations. The extant map has generated a veritable explosion of research and excitement. New distance constraints have been derived for the cloud, using the high fidelity Arecibo map paired with stellar absorption lines. The new distance 11 pc <D <24 pc has allowed us to use the cloud to study the environment of the local ISM. Indeed we have used it to show that the standard Local Hot Bubble paradigm, in which the local cavity is filled with millon degree gas, is incorrect, and that a �??hot-top�?? framework may be more accurate. An expansion of our map will allow us to 1) get better distance constraints to the cloud 2) expand our study of the details of the CNM and 3) get a better X-rays shadowing constraint, which will put the last nail in the coffin of the local hot bubble theory. Top

Are molecular clouds magnetically subcritical or supercritical overall? A survey of Zeeman observations of OH in absorption II. (A2600)
PI �?? Dr. Kristen L Thompson, University of Kentucky
Co-PI �?? Dr. Thomas Troland
Proposal Date: September 30, 2011

Abstract: Although much Zeeman work has been done to study the effect of magnetic fields on molecular cloud cores, very little is known about fields in the general envelopes of molecular clouds. Are molecular clouds as a whole magnetically subcritical or supercritical?Using Arecibo, Thompson and Troland have begun the first systematic observational survey to address this question using the Zeeman effect in OH absorption toward extra-galactic continuum sources that lie behind molecular clouds. In this first survey we have studied 7 lines-of-sight. However, the Zeeman effect can only reveal the line-of-sight magnetic field, which makes this study inherently statistical in nature. To obtain statistically meaningful results for this project, we require magnetic field information for more than 7 lines-of-sight. We have identified 26 additional extra-galactic sources. We will chose about 10 of these sources based upon a short survey of OH optical depths and conduct Zeeman observations, spending about 20 hours on each source. Top

Surveying the Zone of Avoidance with ALFA: Outer Galaxy Region (A2611)
PI �?? Dr. Patricia Henning, University of New Mexico
Co-PI �?? Dr. Travis McIntyre
Proposal Date: December 10th, 2010

Abstract: We propose to survey the Zone of Avoidance (ZOA) deeply at 21-cm using the ALFA system, mapping hidden galaxies and large-scale structures at low Galactic latitudes. Mapping galaxies in the ZOA is one of four large blind surveys endorsed by the Extragalactic ALFA consortium, and is the only low-Galactic latitude project so endorsed. Our project A2152, to conduct deep observations commensally with PALFA, received an "A" grade, and was to observe both the inner and outer Galaxy regions. We are proceeding commensally with PALFA (P2130) in the inner Galaxy region, and propose here that ZOA become primary project in the outer Galaxy region. We refer to our A2152 proposal for full scientific justification. Top

OH Observations of four comets June 2011 - January 2012 (A2616)
PI �?? Dr. Ellen S. Howell, Arecibo Observatory
Co-PI �?? Dr. Amy J. Lovell
Proposal Date: February 6, 2011

Abstract: We propose to continue our measurements of OH lines in cometary comae to measure the water production rates, outflow velocity and study effects of collisional quenching in the inner coma. The radio lines at 1667 and 1665 MHz are ideally suited for study of water in comets from the ground, and can be done in daylight. Two short-period comets and two long-period comets are available in this time period. Top

A search for radio emission from ultracool dwarfs (A2623)
PI �?? Dr. Alexander Wolszczan, Penn State University
Co-PI �?? Dr. Matthew Route
Proposal Date: February 4th, 2011

Abstract: We propose to continue our nearly completed pilot project (a2471) and use the Arecibo telescope with its C-band receiver and the Mock spectrometer to conduct a survey of ultracool dwarfs in search for a burst component of radio emission from these objects. The design of our search has been guided by the unexpected detection of gigahertz radio emission from several ultracool dwarfs, including our own recent first detection of polarized bursts from a T7 brown dwarf, J1047+21. The objectives of this project are to increase the number of detections of ultracool dwarfs to explore the mechanism of both the magnetic field and the radio emission generation in these objects. We are particularly excited about a possibility to explore the brown dwarf - massive planet boundary using magnetic fields as a diagnostic tool. A possibility to probe magnetic fields of the coolest, lowest-mass dwarfs may shed new light on the much debated transition from brown dwarfs to planets, the associated differences in structure, and the most proper way to distinguish between these two types of objects. Top

Continuing the Monitoring of High Latitude OH/IR Stars (A2645)
PI �?? Dr. Murray Lewis
Proposal Date: June 1st, 2011

Abstract: This is a proposal to continue the monitoring of OH masers in high latitude OH/IR stars. It is only ever accorded scraps of time, most in the daytime / twilight gaps of the telescope schedule. Nevertheless, it has resulted in a number of discoveries, including the identification of both �??dead�?? OH/IR stars, stars with revived masers, and a star that has changed from a classic double-peaked to single-peaked spectrum, among others. The proposal seeks to continue this fruitful study, in part by filling in gaps in pulsation-phase coverage that result from the episodic (rather than regular) availability of time. There are two institutional byproducts: (i) more telescope hours are used gainfully, and (ii) OH observations are continued in the 1612 MHz band adjacent to the Iridium satellite band, which helps to maintain the record of this band�??s importance to astronomers. Top

Pilot Observations for a Drift-Scan Pulsar Search at 327 Mhz (P1693)
PI �?? Dr. Paulo C. Freire, NAIC
Co-PI �?? Dr. James Cordes
Proposal Date: June 1st, 2002

Abstract: We request 100hr of telescope time to conduct a pilot drift-scan pulsar search using the new 327 MHz Gregorian receiver and the Wideband Arecibo Pulsar Processor (WAPP). Using a 30-MHz band expected to be available from the new receiver, we will be twice as sensitive to nearby low-DM pulsars as the present 430-MHz drift-scan surveys for pulsars with average spectral indices. The number detectable at 327 MHz should increase by at least a factor of 2. If these expectations are confirmed, we intent to propose a more ambitious all-sky 327-MHz drift-scan survey, which would complement future ALFA (Arecibo L-Band Feed Array) pulsar surveys that would favor pulsars with flatter spectra. Top

An ALFA Pulsar Survey of the Galactic Plane (P2030)
PI �?? Dr. James Cordes, Cornell University
Co-PI �?? Dr. Fernando Camilo
Proposal Date: October 1st, 2004

Abstract: We propose the first year of a large-scale survey of the Galactic plane using ALFA. Primary emphasis will be on the inner Galaxy but we also propose a search of the Galactic anticenter region. Arecibo�??s high gain and wide-band spectrometers allow surveys of much greater volumes (per unit solid angle) than the eminently successful Parkes Multibeam Survey, particularly for short-period pulsars. The survey will thus find not only a large sample of pulsars, but also rare objects that are especially useful for probing fundamental aspects of neutron stars, testing theories of gravity, and detecting gravitational backgrounds, among other enterprises. We estimate that with our eventual software processing, we will discover a pulsar about every 1.5 hr of on-sky observing time. In addition, our analysis also will detect transient signals from pulsars that are intermittent or from other kinds of objects. Preliminary observations in 2004 Aug-Sep have yielded discovery of eight new pulsars in a quick-look analysis, including one from detection of its single pulses. Many more are expected in the data we already have. Given the pace of observations so far, our ability to glean from them new pulsar discoveries, and our expectation that full resolution code will complete the processing of precursor-survey data by the end of 2005 January, a comprehensive pulsar survey using existing WAPP spectrometers can be initiated on or after 2005 Feb 1. Top

Expansion of the NANOGrav Pulsar Timing Array (P2624)
PI �?? Dr. Paul B. Demorest, NRAO
Co-PI �?? Dr. David J. Nice
Proposal Date: February 4, 2011

Abstract: Direct detection of gravitational waves (GW) is a major goal in experimental physics and will revolutionize astrophysics, opening an entirely new spectrum for exploration. Precision pulsar timing stands an excellent chance of being the first method to accomplish this feat. Combining data from many objects into a Pulsar Timing Array (PTA) makes GW detection possible. Increasing the number of pulsars in the array improves sensitivity �?? the detection significance improves approximately linearly with the number of pulsars. Observing more pulsars also helps mitigate intrinsic systematic timing effects. The past year has seen a unexpected and unprecedented number of new millisecond pulsars (MSPs) discovered, due to several ongoing radio sky surveys (GBT 350-MHz surveys; PALFA) and targeted radio searches of Fermi-identified gamma-ray point sources. Here we propose an expansion of our ongoing PTA project to take advantage of these new sources. Top

PSR J1713+0747 with PUPPI: aiming for the best timing even and a new test of general relativity (P2625)
PI �?? Dr. Paulo C. Freire, MPIfR
Co-PI �?? Dr. Paul Demorest
Proposal Date: February 4th, 2011

Abstract: We request time for precise timing of PSR J1713+0747 with the new broadband coherent dedispersion machine, PUPPI. This should result in the most precise pulsar timing ever achieved. We plan a campaign of dense observations that will greatly improve the precision of the orbital and astrometric parameters and enhance the sensitivity of Arecibo�??s timing array to gravitational waves. The improved measurement of the orbital parameters will provide a precise mass value for the pulsar and its companion and greatly improve the precision of a new test of general relativity. The requirements for this (high timing precision and continued timing) are the same as for the detection of gravitational waves. Top

Long-term Timing of the Double Neutron Star PSR B1534+12 (P2628)
PI �?? Dr. Ingrid H Stairs, University of British Columbia
Co-PI �?? Dr. Emmanuel Fonseca
Proposal Date: February 4, 2011

Abstract: Our timing and profile-variation observations of the double-neutron-star binary PSR B1534+12 continue to provide high-precision tests of strong-field gravity and a probe of the general-relativistic geodetic precession rate of the pulsar�??s spin axis. Here we request 6 90-minute observing sessions (approximately LST 1430�??1600) over the course of the next year to monitor changes in the spin properties of and the dispersion measure to this pulsar. These observations are vital to ensure the long-term quality of the data set on this pulsar. Top

An L-band Search for Giant Pulses and Radio Transients in Local Group Galaxies (P2647)
PI �?? Dr. Julia Deneva, Arecibo Observatory
Co-PI �?? Dr. Ramesh Bhat
Proposal Date: June 2nd, 2011

Abstract: We propose to conduct a search for giant pulses (GPs) from Crab-like pulsars in M33 and four dwarf spheroidal (dSph) Local Group galaxies. Using the Mock spectrometer will allow us to achieve superior sensitivity to prior extragalactic pulsar surveys at Arecibo due to its wider bandwidth and better response to radio-frequency interference (RFI) compared with older backends. For M33 observations, ALFA�??s multibeam capability will provide large instantaneous coverage as well as enable efficient elimination of false positives due to sporadic RFI. For observations of dSph galaxies, we will use the even wider-bandwidth L-wide receiver. Both receivers are capable of detecting GPs from Crab-like pulsars in our target galaxies. In addition to important science that will be enabled by extragalactic pulsar discoveries (studies of pulsar population and ISM in each galaxy, and probing the IGM), the algorithms that we develop will also be applicable to science planned with next-generation arrays. Top

Measuring Two Neutron-Star Masses Using Shapiro Delay (P2649)
PI �?? Dr. Patrick Lazarus, McGill University
Co-PI �?? Victoria Kaspi
Proposal Date: June 2nd, 2011

Abstract: Very recently, Demorest et al. (2010, Nature, 467, 1081) measured a pulsar mass of 1.97��0.04 M, thereby greatly extending the known range of precisely measured neutron-star masses, and significantly constraining the equation of state for supra-nuclear-density matter. This major result further emphasizes the questions of (i) how high a neutron-star mass can be?and (ii) what is the true distribution of neutron-star masses? Only through additional, new neutron-star mass measurements can these fundamental questions be answered, but opportunities for this are rare. Here we request 45 hr of Arecibo time in order to measure the Shapiro delay in two PALFA-discovered binary pulsars that are very likely to enable two new precise neutron-star mass measurements. Top

Pulsar Mass Measurements (P2653)
PI �?? Dr. Joris P. Verbiest, Max-Planck-Institut fuer Radioastronomie
Co-PI �?? Dr. Paulo C. Freire
Proposal Date: June 2nd, 2011

Abstract: We plan to use the unique sensitivity of the Arecibo telescope to observe the millisecond pulsar PSR J1640+2224 intensively near superior conjunction, and less intensely during the remainder of the orbit, with the objective of measuring the Shapiro delay for this binary millisecond pulsar. This might confirm the first ever neutron star mass below 1 solar mass. However, even if this is not the case, the planned observations will improve our knowledge of the neutron star mass distribution. Top

Arecibo Radar Observations of Nineteen Near-Earth Asteroids During October 2011-January, 2012 (R2629)
PI �?? Dr. Marina Brozovic, JPL/Caltech
Co-PI �?? Dr. Michael Nolan
Proposal Date: February 4th, 2011

Abstract: We propose to observe 19 near-Earth asteroids via S-band. Due to a high number of exciting objects in period from Oct 2011 to Feb 2012, we propose an ambitious schedule of 153 hours of observing time. Asteroid 2005 YU55 stands out as once-per-decade radar target. This �?400 m diameter object will be at 0.85 lunar distances (LD) on Nov 8, 2011 and the radar data quality will truly be comparable to a spacecraft flyby. Another outstanding target coming in mid-October is Ganymed, which at 40 km diameter is the largest near-Earth object. In the case of Ganymed, we are particularly interested in satellite search. The third highlight is a binary asteroid 1996 FG3 that has been mentioned as the target of interest for the future space missions. We are also very interested in observing asteroids that have been scheduled as targets in the complementary programs such as Spitzer Space Telescope, Wide-field Infrared Survey Explorer (WISE) or NASA InfraRed Telescope Facility (IRTF). We expect that at least 10 out of 19 radar targets will produce datasets suitable for shape modeling. Top

Radar Detection of Six M-class Asteroids (R2632)
PI �?? Dr. Michael K Shepard, Bloomsburg University
Co-PI �?? Dr. Michael Nolan
Proposal Date: February 4th, 2011

Abstract: We propose to observe six M-class asteroids, five of which have never been observed. Our purpose is to continue our systematic investigation into the properties of the M-class asteroids, long thought to be remnant cores of early planetesimals. Successful observation of these six objects will: (1) increase our total sample size of observed M-asteroids by 25% to 25 total objects; and (2) provide a second look at a potential M-class contact binary, 678 Fredegundis. Top

Bistatic radar observations of the Moon with LRO (R2697)
PI �?? Dr. Ben Bussey, JHU/APL
Co-PI �?? Dr. Michael Nolan
Proposal Date: November 14th, 2011

Abstract: We request one track on from 04:00 to 06:000 AST (08:00 to 10:00 UTC) on 2011 Nov 18 to perform initial bistatic observations of the Moon with the Mini-RF instrument on the LRO spacecraft. These will be calibration observations which will be used for the program as well as bolstering our proposal for operational funds for Arecibo to continue this program. Top

Coordinated Incoherent Scatter Radar and Optical Observations during the World Days during 1999-2000 (T1193)
PI �?? Dr. Qihou Zhon, Arecibo Observatory
Co-PI �?? Dr. Nestor Aponte
Proposal Date: October 11, 1998

Abstract: We request the continuation of the World Day program from 1999 through 2000. This is a cooperative effort among all the incoherent scatter radar and optical sites worldwide to investigate the structure, dynamics and composition of the upper atmosphere. The incoherent scatter radar and optical facilities at Arecibo will be used to measure and derive various atmospheric and ionospheric parameters, such as, electron concentration, ion and electron temperature, plasma drift velocity, and neutral wind velocity. The data from all World Day experiments are processed in a common format and archived in the NCAR data base, and are available to investigators from all over the world. Top