- ID:
- ivo://CDS.VizieR/J/AJ/138/338
- Title:
- Arecibo Legacy Fast ALFA Survey. IX.
- Short Name:
- J/AJ/138/338
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of HI sources extracted from the ongoing Arecibo Legacy Fast ALFA (ALFALFA) extragalactic HI line survey, found within the sky region bounded by 9:36<RA<11:36 and +08<DE<+12. The HI catalog presented here for this 118deg^2^ region is combined with the ones derived from surrounding regions also covered by the ALFALFA survey to examine the large-scale structure in the complex Leo region. Because of the combination of wide sky coverage and superior sensitivity, spatial and spectral resolution, the ALFALFA HI catalog of the Leo region improves significantly on the numbers of low HI mass sources as compared with those found in previous HI surveys.
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- ID:
- ivo://CDS.VizieR/J/AJ/135/588
- Title:
- Arecibo legacy fast ALFA survey V.
- Short Name:
- J/AJ/135/588
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a second catalog of HI sources detected in the Arecibo Legacy Fast ALFA Survey. We report 488 detections over 135deg^2^, within the region of the sky having 22<RA<03 and +26<DE<+28. We present here the detections that have either (a) S/N>6.5, where the reliability of the catalog is better than 95% or (b) 5.0<S/N<6.5 and a previously measured redshift that corroborates our detection. Of the 488 objects presented here, 49 are high-velocity clouds or clumps thereof with negative heliocentric recession velocities. These clouds are mostly very compact and isolated, while some of them are associated with large features such as Wright's Cloud or the northern extension of the Magellanic Stream. The remaining 439 candidate detections are identified as extragalactic objects and have all been matched with optical counterparts. Five of the six galaxies detected with M_HI_<10^7.5^ solMass are satellites of either the NGC672/IC1727 nearby galaxy pair or their neighboring dwarf irregular galaxy NGC784. The data of this catalog release include a slice through the Pisces-Perseus foreground void, a large nearby underdensity of galaxies. We report no detections within the void, where our catalog is complete for systems with HI masses of 10^8^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/136/713
- Title:
- Arecibo legacy fast ALFA survey. VI.
- Short Name:
- J/AJ/136/713
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the third installment of HI sources extracted from the Arecibo Legacy Fast ALFA extragalactic survey. This data set continues the work of the Virgo ALFALFA catalog. The catalogs and spectra published here consist of data obtained during the 2005 and 2006 observing sessions of the survey. The catalog consists of 578 HI detections within the range 11h36m<RA(J2000)<13h52m and +08{deg}<DE(J2000)<+12{deg}, and cz_{sun}_<18000km/s. The catalog entries are matched with optical counterparts where possible through the examination of digitized optical images. The catalog detections can be classified into three categories: (a) detections of high reliability with a signal-to-noise ratio (S/N)>6.5; (b) high-velocity clouds in the Milky Way or its periphery; and (c) signals of lower S/N which coincide spatially with an optical object and known redshift. 75% of the sources are newly published HI detections. Of particular note is a complex of HI clouds projected between M87 and M49 that do not coincide with any optical counterparts. Candidate objects without optical counterparts are few. Position corrections for telescope pointing errors are applied to the data set by comparing the ALFALFA continuum centroid with those cataloged in the NRAO VLA Sky Survey (NVSS, Cat. VIII/65). The uncorrected positional accuracy averages 27"(21" median) for all sources with S/N>6.5 and is of order ~21"(16" median) for signals with S/N>12. Uncertainties in distances toward the Virgo cluster can affect the calculated HI mass distribution.
- ID:
- ivo://CDS.VizieR/J/ApJ/656/255
- Title:
- Arecibo methanol maser Galactic Plane Survey
- Short Name:
- J/ApJ/656/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an unbiased survey for 6.7GHz methanol masers in the Galactic plane carried out using the 305m Arecibo radio telescope. A total of 18.2deg^2^ was surveyed with uniform sampling at 35.2<=l<=53.7, |b|<=0.41. The large collecting area of Aecibo and the sensitive C-Band High receiver allowed the survey to be complete at the level of 0.27Jy, making this the most sensitive blind survey carried out to date. We detected a total of 86 sources, 48 of which are new detections. Most of the new detections have a peak flux density below 2Jy. Many methanol masers are clustered, reflecting the formation of massive stars in clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/669/435
- Title:
- Arecibo Methanol Maser Galactic Plane Survey. II.
- Short Name:
- J/ApJ/669/435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the properties of the 6.7GHz methanol maser sample detected in the Arecibo Methanol Maser Galactic Plane Survey. The distribution of the masers in the Galaxy, and statistics of their multiwavelength counterparts is consistent with the hypothesis of 6.7GHz maser emission being associated with massive young stellar objects. Using the detection statistics of our survey, we estimate the minimum number of methanol masers in the Galaxy to be 1275.
- ID:
- ivo://CDS.VizieR/J/ApJS/93/549
- Title:
- Arecibo 1612 MHz survey supplement
- Short Name:
- J/ApJS/93/549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The completeness of the Arecibo 1612 MHz survey of color-selected/IRAS sources (see references) is extended to (25-12){mu}m>-0.7. In addition (1) most IR sources with spectral types normally associated with OH/IR stars and colors outside the coverage of the original survey have been examined; (2) most ambiguous observations during the survey have been reobserved: (3) most single peaked sources have been reexamined, and 17 found with second peaks. We report 39 new 1612MHz detections, of which 34 are original. These are also surveyed in the mainlines. Analysis of the complete flux-limited survey confirms the existence of a longitude sensitivity effect in the detection of sources, which reduces the total number detected by ~4%. This analysis sets an upper limit of 16%, on the proportion of a color-selected sample that may be identified with carbon stars and/or star-formation regions.
- ID:
- ivo://CDS.VizieR/J/AJ/132/1851
- Title:
- Arecibo obs. of formaldehyde in L1551
- Short Name:
- J/AJ/132/1851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of the formaldehyde (H_2_CO) 6cm (4.8GHz) line toward L1551. The observations were conducted with the Arecibo Telescope (beam FWHP~1') to verify the tentative detection of H_2_CO thermal emission reported by Duncan and collaborators in 1987MNRAS.224..721D. The H_2_CO emission lines were expected to be present with a signal-to-noise ratio of >~10 in our spectra. However, we did not detect H_2_CO emission; i.e., our data rule out their tentative detection. The absence of H_2_CO emission is also confirmed by the fact that the H_2_CO line profiles at the two positions of expected emission are well fitted by a single absorption component (accounting for the hyperfine structure of the line) in one of the positions and by a single absorption line plus a red-wing absorption component in the second position. The Orion BN/KL region remains the only H_2_CO 6cm thermal emitter known. Our observations also demonstrate that the H_2_CO 6cm absorption line traces not only the quiescent molecular cloud but also the kinematics associated with the star formation process in L1551-IRS5.
- ID:
- ivo://CDS.VizieR/J/ApJS/121/171
- Title:
- Arecibo polarimetry of 98 pulsars
- Short Name:
- J/ApJS/121/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured full Stokes parameter profiles of 98 pulsars at 21 cm from Arecibo observatory. Average profiles are presented with integration times as long as 1/3 day. We have studied the resulting profiles and other published data on each pulsar and classified them according to the Rankin morphological scheme.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/81
- Title:
- Arecibo Pulsar-ALFA (PALFA) survey. IV.
- Short Name:
- J/ApJ/812/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The on-going Arecibo Pulsar-ALFA (PALFA) survey began in 2004 and is searching for radio pulsars in the Galactic plane at 1.4GHz. Here we present a comprehensive description of one of its main data reduction pipelines that is based on the PRESTO software and includes new interference-excision algorithms and candidate selection heuristics. This pipeline has been used to discover 40 pulsars, bringing the survey's discovery total to 144 pulsars. Of the new discoveries, eight are millisecond pulsars (MSPs; P<10ms) and one is a Fast Radio Burst (FRB). This pipeline has also re-detected 188 previously known pulsars, 60 of them previously discovered by the other PALFA pipelines. We present a novel method for determining the survey sensitivity that accurately takes into account the effects of interference and red noise: we inject synthetic pulsar signals with various parameters into real survey observations and then attempt to recover them with our pipeline. We find that the PALFA survey achieves the sensitivity to MSPs predicted by theoretical models but suffers a degradation for P>~100ms that gradually becomes up to ~10 times worse for P>4s at DM<150pc/cm^3^. We estimate 33+/-3% of the slower pulsars are missed, largely due to red noise. A population synthesis analysis using the sensitivity limits we measured suggests the PALFA survey should have found 224+/-16 un-recycled pulsars in the data set analyzed, in agreement with the 241 actually detected. The reduced sensitivity could have implications on estimates of the number of long-period pulsars in the Galaxy.
- ID:
- ivo://CDS.VizieR/J/MNRAS/505/6051
- Title:
- Arecibo sample variability properties
- Short Name:
- J/MNRAS/505/6051
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of a near-infrared (NIR) monitoring program carried out between 1999 and 2005 to determine the variability properties of the `Arecibo sample of OH/IR stars'. The sample consists of 385 IRAS-selected Asymptotic Giant Branch (AGB) candidates, for which their O-rich chemistry has been proven by the detection of 1612 MHz OH maser emission. The monitoring data was complemented by data collected from public optical and NIR surveys. We fitted the light curves obtained in the optical and NIR bands with a model using an asymmetric cosine function, and derived a period for 345 sources ~90% of the sample). Based on their variability properties, most of the Arecibo sources are classified as long-period large-amplitude variable stars (LPLAV), 4% as (candidate) post-AGB stars, and 3% remain unclassified although they are likely post-AGB stars or highly obscured AGB stars. The period distribution of the LPLAVs peaks at ~400d, with periods between 300 and 800d for most of the sources, and has a long tail up to ~2100d. Typically, the amplitudes are between 1 and 3 mag in the NIR and between 2 and 6 mag in the optical. We find correlations between periods and amplitudes, with larger amplitudes associated to longer periods, as well as between the period and the infrared colours, with the longer periods linked to the redder sources. Among the post-AGB stars, the light curve of IRAS 19566+3423 was exceptional, showing a large systematic increase (>0.4mag/yr) in K-band brightness over 7 years.
