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941. Arecibo methanol maser Galactic Plane Survey
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.
942. Arecibo Methanol Maser Galactic Plane Survey. II.
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.
943. Arecibo 1612 MHz survey supplement
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.
944. Arecibo obs. of formaldehyde in L1551
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.
945. Arecibo Pulsar-ALFA (PALFA) survey. IV.
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.
946. Arecibo sample variability properties
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.
947. A redshift catalog of the galaxy cluster A2029
ID:
ivo://CDS.VizieR/J/ApJ/871/129
Title:
A redshift catalog of the galaxy cluster A2029
Short Name:
J/ApJ/871/129
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explore the structure of galaxy cluster A2029 and its surroundings based on intensive spectroscopy along with X-ray and weak lensing observations. The redshift survey includes 4376 galaxies (1215 spectroscopic cluster members) within 40' of the cluster center; the redshifts are included here. Two subsystems, A2033 and a southern infalling group (SIG), appear in the infall region based on the spectroscopy, as well as on the weak lensing and X-ray maps. The complete redshift survey of A2029 also identifies at least 12 foreground and background systems (10 are extended X-ray sources) in the A2029 field; we include a census of their properties. The X-ray luminosities (L_X_)-velocity dispersions ({sigma}_cl_) scaling relations for A2029, A2033, SIG, and the foreground/background systems are consistent with the known cluster scaling relations. The combined spectroscopy, weak lensing, and X-ray observations provide a robust measure of the masses of A2029, A2033, and SIG. The total mass of the infalling groups (A2033 and SIG) is ~60% of the M200 of the primary cluster, A2029. Simple dynamical considerations suggest that A2029 will accrete these subsystems in the next few Gyr. In agreement with simulations and other clusters observed in a similar redshift range, the total mass in the A2029 infall region is comparable to the A2029 M200 and will mostly be accreted in the long-term future.
948. A redshift survey of the central region of A2199
ID:
ivo://CDS.VizieR/J/ApJ/842/88
Title:
A redshift survey of the central region of A2199
Short Name:
J/ApJ/842/88
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results from an extensive spectroscopic survey of the central region of the nearby galaxy cluster Abell 2199 (A2199) at z=0.03. By combining 775 new redshifts from the MMT/Hectospec observations with the data in the literature, we construct a large sample of 1624 galaxies with measured redshifts at R<30', which results in high spectroscopic completeness at r_petro,0_<20.5 (77%). We use these data to study the kinematics and clustering of galaxies, focusing on the comparison with those of the intracluster medium (ICM) from Suzaku X-ray observations. We identify 406 member galaxies of A2199 at R<30' using the caustic technique. The velocity dispersion profile of cluster members appears smoothly connected to the stellar velocity dispersion profile of the cD galaxy. The luminosity function is well fitted with a Schechter function at M_r_< -15. The radial velocities of cluster galaxies generally agree well with those of the ICM, but there are some regions where the velocity difference between the two is about a few hundred kilometers per second. The cluster galaxies show a hint of global rotation at R<5' with v_rot_=300-600km/s, but the ICM in the same region does not show such rotation. We apply a friends-of-friends algorithm to the cluster galaxy sample at R<60' and identify 32 group candidates, and examine the spatial correlation between the galaxy groups and X-ray emission. This extensive survey in the central region of A2199 provides an important basis for future studies of interplay among the galaxies, the ICM, and the dark matter in the cluster.
949. Are infrared dark clouds really quiescent?
ID:
ivo://CDS.VizieR/J/A+A/592/A21
Title:
Are infrared dark clouds really quiescent?
Short Name:
J/A+A/592/A21
Date:
21 Oct 2021
Publisher:
CDS
Description:
The dense, cold regions where high-mass stars form are poorly characterised, yet they represent an ideal opportunity to learn more about the initial conditions of high-mass star formation (HMSF), since high-mass starless cores (HMSCs) lack the violent feedback seen at later evolutionary stages. We present continuum maps obtained from the Submillimeter Array (SMA) interferometry at 1.1mm for four infrared dark clouds (IRDCs, G28.34S, IRDC 18530, IRDC 18306, and IRDC 18308). We also present 1mm/3mm line surveys using IRAM 30m single-dish observations. Our results are: (1) At a spatial resolution of 10^4^AU, the 1.1mm SMA observations resolve each source into several fragments. The mass of each fragment is on average >10M_{sun}_, which exceeds the predicted thermal Jeans mass of the whole clump by a factor of up to 60, indicating that thermal pressure does not dominate the fragmentation process. Our measured velocity dispersions in the 30m lines imply that non-thermal motions provides the extra support against gravity in the fragments. (2) Both non-detection of high-J transitions and the hyperfine multiplet fit of N_2_H^+^(1-0), C_2_H(1-0), HCN(1-0), and H^13^CN(1-0) indicate that our sources are cold and young. However, obvious detection of SiO and the asymmetric line profile of HCO^+^(1-0) in G28.34S indicate a potential protostellar object and probable infall motion. (3) With a large number of N-bearing species, the existence of carbon rings and molecular ions, and the anti-correlated spatial distributions between N_2_H^+^/NH_2_D and CO, our large-scale high-mass clumps exhibit similar chemical features as small-scale low-mass prestellar objects. This study of a small sample of IRDCs illustrates that thermal Jeans instability alone cannot explain the fragmentation of the clump into cold (~15K), dense (>10^5^cm^-3^) cores and that these IRDCs are not completely quiescent.
950. Argentina High-Latitude H I Survey
ID:
ivo://CDS.VizieR/VIII/9
Title:
Argentina High-Latitude H I Survey
Short Name:
VIII/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
This survey consists of H I 21-cm spectra covering the southern sky with absolute galactic latitude |b|>10 degrees and a declination dec<-25 degrees. The observations were made with the 30m telescope of the Instituto Argentino de Radioastronomia during 1973 to 1977 and were described in Colomb et al. (1977A&AS...29...89C). The data were obtained by keeping the telescope fixed on the meridian at the desired declination and letting the sky drift through the field. The individual spectra were obtained with a 56-channel filterbank and covering the velocity range from about -40 to +40km/s. The velocity resolution is 2km/s, and the beamwidth is 30arcmin.

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