- ID:
- ivo://CDS.VizieR/J/AJ/162/61
- Title:
- Radial velocity follow up of Barnard's star with HPF
- Short Name:
- J/AJ/162/61
- Date:
- 14 Mar 2022 07:00:45
- Publisher:
- CDS
- Description:
- Barnard's star is among the most studied stars given its proximity to the Sun. It is often considered the radial velocity (RV) standard for fully convective stars due to its RV stability and equatorial decl. Recently, an M_sini_=3.3M{Earth} super-Earth planet candidate with a 233day orbital period was announced by Ribas et al. New observations from the near-infrared Habitable-zone Planet Finder (HPF) Doppler spectrometer do not show this planetary signal. We ran a suite of experiments on both the original data and a combined original + HPF data set. These experiments include model comparisons, periodogram analyses, and sampling sensitivity, all of which show the signal at the proposed period of 233days is transitory in nature. The power in the signal is largely contained within 211 RVs that were taken within a 1000 day span of observing. Our preferred model of the system is one that features stellar activity without a planet. We propose that the candidate planetary signal is an alias of the 145day rotation period. This result highlights the challenge of analyzing long-term, quasi-periodic activity signals over multiyear and multi-instrument observing campaigns.
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- ID:
- ivo://CDS.VizieR/J/AJ/160/114
- Title:
- Radial velocity monitoring of TOI-421
- Short Name:
- J/AJ/160/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-141137, TIC94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by the Transiting Exoplanet Survey Satellite (TESS) space mission in Sectors 5 and 6. We performed ground-based follow-up observations-comprised of Las Cumbres Observatory Global Telescope transit photometry, NIRC2 adaptive optics imaging, and FIbre-fed Echelle Spectrograph, CORALIE, High Accuracy Radial velocity Planet Searcher, High Resolution Echelle Spectrometer, and Planet Finder Spectrograph high-precision Doppler measurements-and confirmed the planetary nature of the 16 day transiting candidate announced by the TESS team. We discovered an additional radial velocity signal with a period of five days induced by the presence of a second planet in the system, which we also found to transit its host star. We found that the inner mini-Neptune, TOI-421b, has an orbital period of Pb=5.19672{+/-}0.00049days, a mass of Mb=7.17{+/-}0.66M{Earth}, and a radius of Rb=2.68_-0.18_^+0.19^R{Earth}, whereas the outer warm Neptune, TOI-421c, has a period of Pc=16.06819{+/-}0.00035days, a mass of Mc=16.42_-1.04_^+1.06^M{Earth}, a radius of Rc=5.09_-0.15_^+0.16^R{Earth}, and a density of {rho}c=0.685_-0.072_^+0.080^g/cm^3^. With its characteristics, the outer planet ({rho}c=0.685_-0.072_^+0.080^g/cm^3^) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421b and TOI-421c are found to be well-suited for atmospheric characterization. Our atmospheric simulations predict significant Ly{alpha} transit absorption, due to strong hydrogen escape in both planets, as well as the presence of detectable CH4 in the atmosphere of TOI-421c if equilibrium chemistry is assumed.
- ID:
- ivo://CDS.VizieR/J/ApJ/581/844
- Title:
- Radio and Infrared observations of EROs
- Short Name:
- J/ApJ/581/844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a sensitive multiwavelength analysis of the properties of extremely red objects (EROs). Our analysis employs deep RIzJHK photometry of an 8.5'x8.5' region to select a sample of 68 EROs with (R-K)>=5.3 and brighter than K=20.5 (5{sigma}). We combine this photometric data set with an extremely deep 1.4GHz radio map of the field obtained from the VLA. This map reaches a 1{sigma} limiting flux density of 3.5{mu}Jy , making it the deepest 1.4GHz map taken, and is sensitive enough to detect an active galaxy with L1.4>~10^23^W/Hz at z>1.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/285
- Title:
- Radio and IR counterparts of BLAST sources in CDFS
- Short Name:
- J/ApJ/703/285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified radio and/or mid-infrared counterparts to 198 out of 350 sources detected at >=5{sigma} over ~9deg^2^ centered on the Chandra Deep Field South by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) at 250, 350, and 500um. We have matched 114 of these counterparts to optical sources with previously derived photometric redshifts and fitted spectral energy distributions to the BLAST fluxes and fluxes at 70 and 160um acquired with the Spitzer Space Telescope. In this way, we have constrained dust temperatures, total far-infrared/submillimeter luminosities, and star formation rates for each source. Our findings show that, on average, the BLAST sources lie at significantly lower redshifts and have significantly lower rest-frame dust temperatures compared to submillimeter sources detected in surveys conducted at 850um. We demonstrate that an apparent increase in dust temperature with redshift in our sample arises as a result of selection effects. Finally, we provide the full multiwavelength catalog of >=5{sigma} BLAST sources contained within the complete ~9deg^2^ survey area.
- ID:
- ivo://CDS.VizieR/J/MNRAS/246/169
- Title:
- Radio continuum around G 73.9+0.9
- Short Name:
- J/MNRAS/246/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A field centered on the galactic supernova remnant (SNR) G073.9+00.9 was mapped in the continuum at 408 and 1420 MHz with the Dominion Radio Astrophysical Observatory (DRAO). The interferometer observations, of resolution 3.4x5.8 arcmin^2^ and 1.0x1.7 arcmin^2^ respectively, were complemented with single-dish data so that the resulting maps are sensitive to all structures down to the synthesized beam. Note that this list is part of the DRAO Penticton P-survey Database (Catalog <VIII/55>)
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/4191
- Title:
- Radio emission from radio-quiet quasars
- Short Name:
- J/MNRAS/455/4191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio emission from radio-quiet quasars may be due to star formation in the quasar host galaxy, to a jet launched by the supermassive black hole, or to relativistic particles accelerated in a wide-angle radiatively driven outflow. In this paper, we examine whether radio emission from radio-quiet quasars is a byproduct of star formation in their hosts. To this end, we use infrared spectroscopy and photometry from Spitzer and Herschel to estimate or place upper limits on star formation rates in hosts of ~300 obscured and unobscured quasars at z<1. We find that low-ionization forbidden emission lines such as [NeII] and [NeIII] are likely dominated by quasar ionization and do not provide reliable star formation diagnostics in quasar hosts, while polycyclic aromatic hydrocarbon (PAH) emission features may be suppressed due to the destruction of PAH molecules by the quasar radiation field. While the bolometric luminosities of our sources are dominated by the quasars, the 160{mu}m fluxes are likely dominated by star formation, but they too should be used with caution. We estimate median star formation rates to be 6-29M_{sun}_/yr, with obscured quasars at the high end of this range. This star formation rate is insufficient to explain the observed radio emission from quasars by an order of magnitude, with log(L_radio,obs_/L_radio,SF_)=0.6-1.3 depending on quasar type and star formation estimator. Although radio-quiet quasars in our sample lie close to the 8-1000{mu}m infrared/radio correlation characteristic of the star-forming galaxies, both their infrared emission and their radio emission are dominated by the quasar activity, not by the host galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A19
- Title:
- Radio-farIR correlation in NGC 6946
- Short Name:
- J/A+A/552/A19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the distribution of the synchrotron spectral index across NGC 6946 and investigate the correlation between the radio continuum (synchrotron) and far-infrared (FIR) emission using the KINGFISH Herschel PACS and SPIRE data.
- ID:
- ivo://CDS.VizieR/J/ApJS/166/567
- Title:
- Radio Molecular lines in infrared dark clouds
- Short Name:
- J/ApJS/166/567
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified 41 infrared dark clouds from the 8um maps of the Midcourse Space Experiment (MSX), selected to be found within 1deg^2^ areas centered on known ultracompact HII regions. We have mapped these infrared dark clouds in N_2_H^+^ 1->0, CS 2->1, and C^18^O 1->0 emission using the Five College Radio Astronomy Observatory. The maps of the different species often show striking differences in morphologies, indicating differences in evolutionary state and/or the presence of undetected, deeply embedded protostars. We derive an average mass for these clouds using N_2_H^+^ column densities of >>2500M_{sun}_, a value comparable to that found in previous studies of high-mass star-forming cores using other mass tracers. The line widths of these clouds are typically 2.0-2.9km/s. Based on the fact that they are dark at 8um, compact, and massive, and have large velocity dispersions, we suggest that these clouds may be the precursor sites of intermediate- and high-mass star formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/383/479
- Title:
- Radio obs. of optically obscured galaxies
- Short Name:
- J/MNRAS/383/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper analyses the radio properties of a subsample of optically obscured (R>=25.5) galaxies observed at 24um by the Spitzer Space Telescope within the First Look Survey. Ninety-six F24um>=0.35mJy objects out of 510 are found to have a radio counterpart at 1.4GHz, 610MHz or at both frequencies, respectively, down to ~40 and ~200uJy. IRAC photometry sets the majority of them in the redshift interval z~=[1-3] and allows for a broad distinction between active galactic nucleus (AGN) dominated galaxies (~47 per cent of the radio-identified sample) and systems powered by intense star formation (~13 per cent), the remaining objects being impossible to classify. The percentage of radio identifications is a strong function of 24-um flux: almost all sources brighter than F_24um_~2mJy are endowed with a radio flux at both 1.4GHz and 610MHz, while this fraction drastically decreases by lowering the 24-um flux level.
- ID:
- ivo://CDS.VizieR/J/ApJ/886/48
- Title:
- Radio & opt/NIR counterparts of S2COSMOS submm galaxies
- Short Name:
- J/ApJ/886/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify multi-wavelength counterparts to 1147 submillimeter sources from the S2COSMOS SCUBA-2 survey of the COSMOS field by employing a recently developed radio+machine-learning method trained on a large sample of Atacama Large Millimeter/submillimeter Array (ALMA)-identified submillimeter galaxies (SMGs), including 260 SMGs identified in the AS2COSMOS pilot survey. In total, we identify 1222 optical/near-infrared (NIR)/radio counterparts to the 897 S2COSMOS submillimeter sources with S_850_>1.6mJy, yielding an overall identification rate of (78+/-9)%. We find that (22+/-5)% of S2COSMOS sources have multiple identified counterparts. We estimate that roughly 27% of these multiple counterparts within the same SCUBA-2 error circles very likely arise from physically associated galaxies rather than line-of-sight projections by chance. The photometric redshift of our radio+machine-learning-identified SMGs ranges from z=0.2 to 5.7 and peaks at z=2.3+/-0.1. The AGN fraction of our sample is (19+/-4)%, which is consistent with that of ALMA SMGs in the literature. Comparing with radio/NIR-detected field galaxy population in the COSMOS field, our radio+machine-learning-identified counterparts of SMGs have the highest star formation rates and stellar masses. These characteristics suggest that our identified counterparts of S2COSMOS sources are a representative sample of SMGs at z<~3. We employ our machine-learning technique to the whole COSMOS field and identified 6877 potential SMGs, most of which are expected to have submillimeter emission fainter than the confusion limit of our S2COSMOS surveys (S_850um_<~1.5mJy). We study the clustering properties of SMGs based on this statistically large sample, finding that they reside in high-mass dark matter halos ((1.2+/-0.3)x10^13^h^-1^M_{sun}_), which suggests that SMGs may be the progenitors of massive ellipticals we see in the local universe.
