- ID:
- ivo://CDS.VizieR/J/A+A/627/A162
- Title:
- L1489 starless core carbon-chain-producing region
- Short Name:
- J/A+A/627/A162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of a particular carbon-chain-producing region, L1489 starless core (L1489 EMC), which is located at 1-arcmin east of L1489 IRS. We detected carbon-chain molecules (CCMs) HC_2_n+1N (n=1-3) and C_3_S in Ku band as well as high-energy excitation lines including C_4_H N=9-8, J=17/2-15/2, 19/2-17/2, and CH_3_CCH J=5-4, K=2 in the 3mm band toward a starless core called the eastern molecular core (EMC) of L1489 IRS. Maps of all the observed lines were also obtained. Comparisons with a number of early starless cores and WCCC source L1527 show that the column densities of C_4_H and CH_3_CCH are close to those of L1527, and the CH_3_CCH column densities of the EMC and L1527 are slightly higher than those of TMC-1. The EMC and L1527 have similar C3S column densities, but they are much lower than those of all the starless cores, with only 6.5% and 10% of the TMC-1 value, respectively. The emissions of the N-bearing species of the EMC and L1527 are at the medium level of the starless cores. These comparisons show that the CCM emissions in the EMC are similar to those of L1527, though L1527 contains a protostar. Although dark and quiescent, the EMC is warmer and at a later evolutionary stage than classical carbon-chain-producing regions in the cold, dark, quiescent early phase. The PACS, SPIRE, and SCUBA maps evidently show that the L1489 IRS seems to be the heating source of the EMC. Although it is located at the margins of the EMC, its bolometric luminosity and bolometric temperature are relatively high. Above all, the EMC is a rather particular carbon-chain-producing region and is quite significant for CCM science.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/275/163
- Title:
- Luminous Carbon stars in Galactic Plane
- Short Name:
- J/A+A/275/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of distant (2-10kpc), heavily obscured asymptotic giant branch (AGB) stars were observed for CO emission. Simultaneous observations at the frequencies of the J=1-0 (115.27GHz) and J=2-1 (230.58GHz) transitions of CO were made at the 30m IRAM telescope on Pico Velata, Spain, in September 1989.
- ID:
- ivo://CDS.VizieR/J/ApJ/846/44
- Title:
- Luminous persistent sources in nearby galaxies search
- Short Name:
- J/ApJ/846/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The localization of the repeating fast radio burst (FRB), FRB 121102, suggests that it is associated with a persistent radio-luminous compact source in the FRB host galaxy. Using the FIRST radio catalog, I present a search for luminous persistent sources in nearby galaxies, with radio luminosities >10% of the FRB 121102 persistent source luminosity. The galaxy sample contains about 30% of the total galaxy g-band luminosity within <108Mpc, in a footprint of 10600deg^2^. After rejecting sources likely due to active galactic nuclei activity or background sources, I am left with 11 candidates that are presumably associated with galactic disks or star-formation regions. At least some of these candidates are likely to be due to chance alignment. In addition, I find 85 sources within 1" of galactic nuclei. Assuming that the radio persistent sources are not related to galactic nuclei and that they follow the galaxy g-band light, the 11 sources imply a 95% confidence upper limit on the space density of luminous persistent sources of <~5x10^-5^Mpc^-3^, and that at any given time only a small fraction of galaxies host a radio-luminous persistent source (<~10^-3^L_*_^-1^). Assuming a persistent source lifetime of 100 years, this implies a birth rate of <~5x10^-7^yr^-1^Mpc^-3^. Given the FRB volumetric rate, and assuming that all FRBs repeat and are associated with persistent radio sources, this sets a lower limit on the rate of FRB events per persistent source of >~0.8yr^-1^. I argue that these 11 candidates are good targets for FRB searches and I estimate the FRB event rate from these candidates.
- ID:
- ivo://CDS.VizieR/J/ApJS/222/12
- Title:
- Luminous X-ray candidates within D25 of galaxies
- Short Name:
- J/ApJS/222/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Chandra archive data we conduct a thorough survey of luminous X-ray sources. We directly analyze about 9400 ACIS Observations and cross-correlate the X-ray sources with 77000 galaxies within 250Mpc. The final catalog includes 119 unique luminous X-ray source candidates with L_X_>3x10^40^erg/s from 93 galaxies or 41 HLX candidates with L_X_>1x10^41^erg/s from 35 galaxies. We derive a moderate contamination rate due to foreground or background sources. We also cross-correlate the catalog with FIRST, perform variability and periodicity tests, and analyze one HLX candidate in particular. Our catalog could be a starting point to perform follow-up observations.
- ID:
- ivo://CDS.VizieR/J/A+AS/80/215
- Title:
- Lunar occultations of weak radio sources
- Short Name:
- J/A+AS/80/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the results of lunar occultation observations of 106 radio sources within declination +/- 19 degrees at 327 MHz. There are 171 sources listed in the catalog due to multiple components for some of the radio sources. Flux densities were measured at 327 MHz by lunar occultation with the Ooty Telescope. Flux densities have also been measured at 18 cm (1669 MHz) and 21 cm (1413 MHz) using the Nancay telescope. Optical identifications on the basis of the radio positions and angular structures are given. This catalog is a merge of table 1 and table 2 from the publication.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A77
- Title:
- Lyra system LoFAR and XMM images
- Short Name:
- J/A+A/630/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Diffuse radio emission associated with the intra-cluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that in mergers a fraction of the kinetic energy is channeled into non-thermal components, such as turbulence, cosmic rays and magnetic fields, that may lead to the formation of giant synchrotron sources in the ICM. Studying merging galaxy clusters in different evolutionary phases is fundamental to understanding the origin of radio emission in the ICM. We observed the nearby galaxy cluster pair RXC J1825.3+3026 (z~0.065) and CIZA J1824.1+3029 (z~0.071) at 120-168MHz with the LOw Frequency ARray (LOFAR) and made use of a deep (240 ks) XMM-Newton dataset to study the nonthermal and thermal properties of the system. RXC J1825.3+3026 is in a complex dynamical state, with a primary on-going merger in the E-W direction and a secondary later stage merger with a group of galaxies in the SW, while CIZA J1824.1+3029 is dynamically relaxed. These two clusters are in a pre-merger phase. We report the discovery of a Mpc-scale radio halo with a low surface brightness extension in RXC J1825.3+3026 that follows the X-ray emission from the cluster center to the remnant of a galaxy group in the SW. This is among the least massive systems and the faintest giant radio halo known to date. Contrary to this, no diffuse radio emission is observed in CIZA J1824.1+3029 nor in the region between the pre-merger cluster pair. The power spectra of the X-ray surface brightness fluctuations of RXC J1825.3+3026 and CIZA J1824.1+3029 are in agreement with the findings for clusters exhibiting a radio halo and the ones where no radio emission has been detected, respectively. We provide quantitative support to the idea that cluster mergers play a crucial role in the generation of non-thermal components in the ICM.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A2
- Title:
- MACS J0717.5+3745 polarization int. maps
- Short Name:
- J/A+A/657/A2
- Date:
- 21 Mar 2022 09:20:37
- Publisher:
- CDS
- Description:
- We present wideband (1-6.5 GHz) polarimetric observations, obtained with the Karl G. Jansky Very Large Array (VLA), of the merging galaxy cluster MACS J0717.5+3745, which hosts one of the most complex known radio relic and halo systems. We use both Rotation Measure Synthesis and QU-fitting, and find a reasonable agreement of the results obtained with these methods, in particular, when the Faraday distribution is simple and the depolarization is mild. The relic is highly polarized over its entire length (850kpc), reaching a fractional polarization >30% in some regions. We also observe a strong wavelength-dependent depolarization for some regions of the relic. The northern part of the relic shows a complex Faraday distribution suggesting that this region is located in or behind the intracluster medium (ICM). Conversely, the southern part of the relic shows a Rotation Measure very close to the Galactic foreground, with a rather low Faraday dispersion, indicating very little magnetoionic material intervening the line-of-sight. From spatially resolved polarization analysis, we find that the scatter of Faraday depths correlates with the depolarization, indicating that the tangled magnetic field in the ICM causes the depolarization. We conclude that the ICM magnetic field could be highly turbulent. At the position of a well known narrow-angle-tailed galaxy (NAT), we find evidence of two components clearly separated in Faraday space. The high Faraday dispersion component seems to be associated with the NAT, suggesting the NAT is embedded in the ICM while the southern part of the relic lies in front of it. If true, this implies that the relic and this radio galaxy are not necessarily physically connected and thus, the relic may be not powered by the shock re-acceleration of fossil electrons from the NAT. The magnetic field orientation follows the relic structure indicating a well-ordered magnetic field. We also detect polarized emission in the halo region; however the absence of significant Faraday rotation and a low value of Faraday dispersion suggests the polarized emission, previously considered as the part of the halo, has a shock(s) origin.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A1
- Title:
- Maggie filament datacubes
- Short Name:
- J/A+A/657/A1
- Date:
- 21 Mar 2022 09:19:29
- Publisher:
- CDS
- Description:
- The atomic phase of the interstellar medium plays a key role in the formation process of molecular clouds. Due to the line-of-sight confusion in the Galactic plane that is associated with its ubiquity, atomic hydrogen emission has been challenging to study. We investigate the physical properties of the "Maggie" filament, a large-scale filament identified in HI emission at line-of-sight velocities, v_LSR_~-54km/s. Employing the high-angular resolution data from The HI/OH Recombination line survey of the inner Milky Way (THOR), we have been able to study HI emission features at negative v_LSR_ velocities without any line-of-sight confusion due to the kinematic distance ambiguity in the first Galactic quadrant. In order to investigate the kinematic structure, we decomposed the emission spectra using the automated Gaussian fitting algorithm GaussPy+. We identify one of the largest, coherent, mostly atomic HI filaments in the Milky Way. The giant atomic filament Maggie, with a total length of 1.2+/-0.1kpc, is not detected in most other tracers, and it does not show signs of active star formation. At a kinematic distance of 17kpc, Maggie is situated below (by ~500pc), but parallel to, the Galactic HI disk and is trailing the predicted location of the Outer Arm by 5-10km/s in longitude-velocity space. The centroid velocity exhibits a smooth gradient of less than 3(km/s)/(10pc) and a coherent structure to within +/-6km/s. The line widths of ~10km/s along the spine of the filament are dominated by nonthermal effects. After correcting for optical depth effects, the mass of Maggie's dense spine is estimated to be 7.2x10^5^ solar masses. The mean number density of the filament is ~4cm^-3^, which is best explained by the filament being a mix of cold and warm neutral gas. In contrast to molecular filaments, the turbulent Mach number and velocity structure function suggest that Maggie is driven by transonic to moderately supersonic velocities that are likely associated with the Galactic potential rather than being subject to the effects of self-gravity or stellar feedback. The probability density function of the column density displays a log-normal shape around a mean of 4.8x10^20^cm^-2^, thus reflecting the absence of dominating effects of gravitational contraction.
- ID:
- ivo://CDS.VizieR/J/ApJ/688/1029
- Title:
- Magnetic field in the SMC
- Short Name:
- J/ApJ/688/1029
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the magnetic field of the Small Magellanic Cloud (SMC), carried out using radio Faraday rotation and optical starlight polarization data. Consistent negative rotation measures (RMs) across the SMC indicate that the line-of-sight magnetic field is directed uniformly away from us with a strength 0.19+/-0.06{mu}G. Applying the Chandrasekhar-Fermi method to starlight polarization data yields an ordered magnetic field in the plane of the sky of strength 1.6+/-0.4uG oriented at a position angle 4+/-12{deg}, measured counterclockwise from the great circle on the sky joining the SMC to the Large Magellanic Cloud (LMC). We construct a three-dimensional magnetic field model of the SMC, under the assumption that the RMs and starlight polarization probe the same underlying large-scale field. further test the pan-Magellanic field hypothesis.
- ID:
- ivo://CDS.VizieR/J/AZh/94/598
- Title:
- Magnetic fields of radio pulsars
- Short Name:
- J/AZh/94/598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mechanism of magnetodipole braking of radio pulsars is used to calculate new values of the surface magnetic fields of neutron stars. The angles {beta} between the spin axes and magnetic moments of the neutron stars were estimated for 376 radio pulsars using three different methods. It is shown that small inclinations of magnetic axes dominate. The equatorial magnetic fields for the considered sample of pulsars are calculated using the {beta} values obtained. As a rule, these magnetic fields are a factor of a few higher than the corresponding values in known catalogs.
