- ID:
- ivo://astron.nl/arts_dr2/q/obs_cone
- Title:
- Apertif Time Domain FRB observation cone search (DR2)
- Short Name:
- Observed FRBs
- Date:
- 31 Jul 2024 11:50:27
- Publisher:
- ASTRON
- Description:
- This is the final, full data release from the Apertif Radio Transient System (ARTS), a supercomputing radio-telescope instrument that performed real-time FRB detection and localisation on the Westerbork Synthesis Radio Telescope (WSRT) interferometer. It reached coherent-addition sensitivity over the entire field of the view of the primary- dish beam. The Apertif FRB survey (ALERT) detected 24 new FRBs, and interferometrically localised each of these to 0.4−10 sq. arcmin. All detections are broad band and very narrow, of order 1 ms duration, with high dispersion measures. Please note that the ARTS DR2 collection includes all data from the DR1 collection.
Number of results to display per page
Search Results
- ID:
- ivo://astron.nl/arts_dr1/q/obs_cone
- Title:
- Apertif Time Domain FRB observation cone search (DR1)
- Short Name:
- Observed FRBs
- Date:
- 31 Jul 2024 11:50:09
- Publisher:
- ASTRON
- Description:
- This is the first release of data from the Apertif Radio Transient System (ARTS), a supercomputing radio-telescope instrument that performs real-time FRB detection and localisation on the Westerbork Synthesis Radio Telescope (WSRT) interferometer. It reaches coherent-addition sensitivity over the entire field of the view of the primary- dish beam. After commissioning results verified the system performed as planned, we initiated the Apertif FRB survey (ALERT). Over the first 5 weeks we observed at design sensitivity in 2019, we detected 5 new FRBs, and interferometrically localised each of these to 0.4−10 sq. arcmin. All detections are broad band and very narrow, of order 1 ms duration, and unscattered. Dispersion measures are generally high. Please note that the ARTS DR1 collection available from this end-point is superseded by the ARTS DR2 collection. DR2 includes all data from the DR1 collection that can be queried here. The ARTS DR2 FRB observation cone search can be reached at https://vo.astron.nl/arts_dr2/q/obs_cone/form.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A89
- Title:
- Aperture-corrected SN Ia host properties
- Short Name:
- J/A+A/659/A89
- Date:
- 11 Mar 2022 07:19:46
- Publisher:
- CDS
- Description:
- We use type Ia supernova (SN Ia) data obtained by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II SNS) in combination with the publicly available SDSS DR16 fiber spectroscopy of supernova (SN) host galaxies to correlate SN Ia light-curve parameters and Hubble residuals with several host galaxy properties. Fixed-aperture fiber spectroscopy suffers from aperture effects: the fraction of the galaxy covered by the fiber varies depending on its projected size on the sky, and thus measured properties are not representative of the whole galaxy. The advent of integral field spectroscopy has provided a way to correct the missing light, by studying how these galaxy parameters change with the aperture size. Here we study how the standard SN host galaxy relations change once global host galaxy parameters are corrected for aperture effects. We recover previous trends on SN Hubble residuals with host galaxy properties, but we find that discarding objects with poor fiber coverage instead of correcting for aperture loss introduces biases into the sample that affect SN host galaxy relations. The net effect of applying the commonly used g-band fraction criterion is that intrinsically faint SNe Ia in high-mass galaxies are discarded, thus artificially increasing the height of the mass step by 0.02 mag and its significance. Current and next-generation fixed-aperture fiber-spectroscopy surveys, such as DES, DESI, or TiDES in 4MOST, that aim to study SN and galaxy correlations must consider, and correct for, these effects.
- ID:
- ivo://CDS.VizieR/J/ApJ/671/333
- Title:
- Aperture photometry in NGC 5194
- Short Name:
- J/ApJ/671/333
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have studied the relationship between the star formation rate (SFR), surface density, and gas surface density in the spiral galaxy M51a (NGC 5194), using multiwavelength data obtained as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS). We introduce a new SFR index based on a linear combination of Halpha emission-line and 24um continuum luminosities, which provides reliable extinction-corrected ionizing fluxes and SFR densities over a wide range of dust attenuations.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A6
- Title:
- Aperture photometry of the M31 PHAT clusters
- Short Name:
- J/A+A/654/A6
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- This study is the sixth of a series that investigates degeneracy and stochasticity problems present in the determination of the age, mass, extinction, and metallicity of partially resolved or unresolved star clusters in external galaxies when using Hubble Space Telescope broadband photometry. In the fifth publication, it was noticed that inconsistencies in cluster colour indices, which arise due to projected foreground and background stars on the apertures, enhance age-metallicity-extinction degeneracies. In this work we aim to present new aperture photometry results for a sample of star clusters from the M31 Panchromatic Hubble Andromeda Treasury (PHAT) survey. We employed two methods of aperture photometry. The first method is ordinary aperture photometry to measure total cluster fluxes. The second method was introduced to avoid the brightest foreground and background stars that project onto large apertures. This method employs smaller apertures, adapted to cover a central part of clusters, and applies an aperture correction, derived for the F475W passband, to other passbands.We note that this procedure is valid only for clusters without prominent systematic gradients of colour indices beyond half-light radii. We present two catalogues of star cluster aperture photometry (produced by applying ordinary aperture photometry and adaptive aperture photometry methods) with estimated uncertainties for a sample of 1181 star clusters from the M31 PHAT survey. Compared to the M31 PHAT fundamental star cluster aperture photometry catalogue published by Johnson et al., there are changes made in the following: cluster centre coordinates, aperture sizes, and sky background estimates.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A24
- Title:
- Aperture-synthesis imaging of Antares
- Short Name:
- J/A+A/555/A24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present aperture-synthesis imaging of the red supergiant Antares (alpha Sco) in the CO first overtone lines. Our goal is to probe the structure and dynamics of the outer atmosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/607/A78
- Title:
- APEX and IRAM spectra of CK Vul (Nova 1670)
- Short Name:
- J/A+A/607/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CK Vulpeculae (CK Vul) is an enigmatic star whose outburst was observed in 1670-72. A stellar-merger event was proposed to explain its ancient eruption. We aim to investigate the composition of the molecular gas recently discovered in the remnant of CK Vul. Deriving the chemical, elemental, and isotopic composition is crucial for identifying the nature of the object and obtaining clues on its progenitor(s). We observed millimeter and submillimeter-wave spectra of CK Vul using the IRAM 30m and APEX telescopes. Radiative-transfer modeling of the observed molecular features was performed to yield isotopic ratios for various elements. The spectra of CK Vul reveal a very rich molecular environment of low excitation (T_ex_~<12K). Atomic carbon and twenty seven different molecules, including two ions, were identified. They range from simple diatomic to complex polyatomic species of up to seven atoms large. The chemical composition of the molecular gas is indicative of carbon and nitrogen-driven chemistry but oxides are also present. Additionally, the abundance of F may be enhanced. The spectra are rich in isotopologues that are very rare in most known sources. All stable isotopes of C, N, O, Si, and S are observed and their isotopic ratios are derived. The composition of the remnant's molecular gas is most peculiar and gives rise to a very unique millimeter and submillimeter spectrum. The observation of ions and complex molecules suggests the presence of a photoionizing source but its nature (a central star or shocks) remains unknown. The elemental and isotopic composition of the gas cannot be easily reconciled with standard nucleosynthesis but processing in hot CNO cycles and partial He burning can explain most of the chemical peculiarities. The isotopic ratios of CK Vul are remarkably close to those of presolar nova grains but the link of Nova 1670 to objects responsible for these grains is unclear.
1068. APEX-CHAMP^+^. II.
- ID:
- ivo://CDS.VizieR/J/A+A/507/1425
- Title:
- APEX-CHAMP^+^. II.
- Short Name:
- J/A+A/507/1425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origin and heating mechanisms of warm (50<T<200K) molecular gas in low-mass young stellar objects (YSOs) are strongly debated. Both passive heating of the inner collapsing envelope by the protostellar luminosity as well as active heating by shocks and by UV associated with the outflows or accretion have been proposed. Most data so far have focussed on the colder gas component. We aim to characterize the warm gas within protosteller objects, and disentangle contributions from the (inner) envelope, bipolar outflows and the quiescent cloud. ************************************************************************** * * * Sorry, but the author(s) never supplied the tabular material * * announced in the paper * * * **************************************************************************
- ID:
- ivo://CDS.VizieR/J/A+A/608/A102
- Title:
- APEX CO and HI observations of Lupus I
- Short Name:
- J/A+A/608/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lupus I cloud is found between the Upper Scorpius (USco) and Upper Centaurus-Lupus (UCL) subgroups of the Scorpius-Centaurus OB association, where the expanding USco HI shell appears to interact with a bubble currently driven by the winds of the remaining B stars of UCL. Aims. We investigate whether the Lupus I molecular could have formed in a colliding flow, and in particular, how the kinematics of the cloud might have been influenced by the larger scale gas dynamics. We performed APEX ^13^CO(2-1)and C^18^O(2-1) line observations of three distinct parts of Lupus I that provide kinematic information on the cloud at high angular and spectral resolution. We compare those results to the atomic hydrogen data from the GASS HI survey and our dust emission results presented in the previous paper. Based on the velocity information, we present a geometric model for the interaction zone between the USco shell and the UCL wind bubble. We present evidence that the molecular gas of Lupus Iis tightly linked to the atomic material of the USco shell. The CO emission in Lupus Iis found mainly at velocities between v_LSR_=3-6km/s, which is in the same range as the HI velocities. Thus, the molecular cloud is co-moving with the expanding USco atomic HI shell. The gas in the cloud shows a complex kinematic structure with several line-of-sight components that overlay each other. The nonthermal velocity dispersion is in the transonic regime in all parts of the cloud and could be injected by external compression. Our observations and the derived geometric model agree with a scenario in which Lupus Iis located in the interaction zone between the USco shell and the UCL wind bubble. The kinematics observations are consistent with a scenario in which the Lupus Icloud formed via shell instabilities. The particular location of Lupus I between USco and UCL suggests that counterpressure from the UCL wind bubble and pre-existing density enhancements, perhaps left over from the gas stream that formed the stellar subgroups, may have played a role in its formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/767/36
- Title:
- APEX observations of HOPS protostars
- Short Name:
- J/ApJ/767/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a census of the reddest, and potentially youngest, protostars in the Orion molecular clouds using data obtained with the PACS instrument on board the Herschel Space Observatory and the LABOCA and SABOCA instruments on APEX as part of the Herschel Orion Protostar Survey (HOPS). A total of 55 new protostar candidates are detected at 70{mu}m and 160{mu}m that are either too faint (m_24_>7mag) to be reliably classified as protostars or undetected in the Spitzer/MIPS 24{mu}m band. We find that the 11 reddest protostar candidates with log{lambda}F_{lambda}_70/{lambda}F_{lambda}_24>1.65 are free of contamination and can thus be reliably explained as protostars. The remaining 44 sources have less extreme 70/24 colors, fainter 70{mu}m fluxes, and higher levels of contamination. Taking the previously known sample of Spitzer protostars and the new sample together, we find 18 sources that have log{lambda}F_{lambda}_70/{lambda}F_{lambda}_24>1.65; we name these sources "PACS Bright Red sources," or PBRs. Our analysis reveals that the PBR sample is composed of Class 0 like sources characterized by very red spectral energy distributions (SEDs; T_bol_<45K) and large values of sub-millimeter fluxes (L_smm_/L_bol_>0.6%). Modified blackbody fits to the SEDs provide lower limits to the envelope masses of 0.2-2M_{sun}_ and luminosities of 0.7-10L_{sun}_. Based on these properties, and a comparison of the SEDs with radiative transfer models of protostars, we conclude that the PBRs are most likely extreme Class 0 objects distinguished by higher than typical envelope densities and hence, high mass infall rates.
