- ID:
- ivo://CDS.VizieR/J/A+A/621/A62
- Title:
- 4 LMC SFRs velocity profile maps
- Short Name:
- J/A+A/621/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of our study is to investigate the physical properties of the star-forming interstellar medium (ISM) in the Large Magellanic Cloud (LMC) by separating the origin of the emission lines spatially and spectrally. The LMC provides a unique local template to bridge studies in the Galaxy and high redshift galaxies because of its low metallicity and proximity, enabling us to study the detailed physics of the ISM in spatially resolved individual star-forming regions. Following Okada et al. (2015A&A...580A..54O), we investigate different phases of the ISM traced by carbon-bearing species in four star-forming regions in the LMC, and model the physical properties using the KOSMA-{tau} PDR model. We mapped 3-13 arcmin^2^ areas in 30 Dor, N158, N160, and N159 along the molecular ridge of the LMC in [C II] 158 {mu}m with GREAT on board SOFIA. We also observed the same area with CO(2-1) to (6-5), ^13^CO(2-1) and (3-2), [C I] ^3^P_1_-^3^P_0_ and ^3^P_2_-^3^P_1_ with APEX. For selected positions in N159 and 30 Dor, we observed [O I] 145 {mu}m and [O I] 63 {mu}m with upGREAT. All spectra are velocity resolved. In all four star-forming regions, the line profiles of CO, ^13^CO, and [C I] emission are similar, being reproduced by a combination of Gaussian profiles defined by CO(3-2), whereas [C II] typically shows wider line profiles or an additional velocity component. At several positions in N159 and 30 Dor, we observed the velocity-resolved [O I] 145 and 63 {mu}m lines for the first time. At some positions, the [O I] line profiles match those of CO, at other positions they are more similar to the [C II] profiles. We interpret the different line profiles of CO, [C II] and [O I] as contributions from spatially separated clouds and/or clouds in different physical phases, which give different line ratios depending on their physical properties. We modeled the emission from the CO, [C I], [C II], and [O I] lines and the far-infrared continuum emission using the latest KOSMA-{tau} PDR model, which treats the dust-related physics consistently and computes the dust continuum SED together with the line emission of the chemical species. We find that the line and continuum emissions are not well-reproduced by a single clump ensemble. Toward the CO peak at N159 W, we propose a scenario that the CO, [C II], and [O I] 63 {mu}m emission are weaker than expected because of mutual shielding among clumps.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/483/299
- Title:
- Local Bubble & Gould Belt polarization
- Short Name:
- J/MNRAS/483/299
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We create and analyse the largest up-to-date all-sky compilation of the interstellar optical polarization data supplemented by the reddening data This compilation includes 13 data sources with optical interstellar linear polarization for 3871 Gaia DR2 and Hipparcos stars within 500pc, which do not exhibit a considerable intrinsic polarization. These data are analysed together with five 3D maps and models of the reddening E(B-V). We consider variations of the polarization degree P, position angle theta, and polarization efficiency P/E(B-V) with Galactic coordinates, distance R, and dereddened colour. P shows a maximum at the Gould Belt mid-plane. P/R drops in the Local Bubble by several times defining a boundary of the Bubble at P=0.1 per cent. All the data sources of the reddening, except Lallement et al., show a drop of P/E(B-V) in the Bubble. The spatial- and colour-dependent variations of P and E(B-V) outside the Bubble compensate each other, resulting in a nearly constant P/E(B-V). A giant envelope of aligned dust dominates at middle and high latitudes outside the Bubble. The Markkanen's cloud, the North Polar Spur, and some other filaments are parts of this envelope.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A134
- Title:
- LOFAR census of non-recycled pulsars
- Short Name:
- J/A+A/591/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present first results from a LOFAR census of non-recycled pulsars. The census includes almost all such pulsars known (194 sources) at declinations Dec>8{deg} and Galactic latitudes |Gb|>3{deg}, regardless of their expected flux densities and scattering times. Each pulsar was observed for >=20minutes in the contiguous frequency range of 110-188MHz. Full-Stokes data were recorded. We present the dispersion measures, flux densities, and calibrated total intensity profiles for the 158 pulsars detected in the sample. The median uncertainty in census dispersion measures (1.5x10^-3^pc/cm^3^) is ten times smaller, on average, than in the ATNF pulsar catalogue. We combined census flux densities with those in the literature and fitted the resulting broadband spectra with single or broken power-law functions. For 48 census pulsars such fits are being published for the first time. Typically, the choice between single and broken power-laws, as well as the location of the spectral break, were highly influenced by the spectral coverage of the available flux density measurements. In particular, the inclusion of measurements below 100MHz appears essential for investigating the low-frequency turnover in the spectra for most of the census pulsars. For several pulsars, we compared the spectral indices from different works and found the typical spread of values to be within 0.5-1.5, suggesting a prevailing underestimation of spectral index errors in the literature. The census observations yielded some unexpected individual source results, as we describe in the paper. Lastly, we will provide this unique sample of wide-band, low-frequency pulse profiles via the European Pulsar Network Database.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A75
- Title:
- LOFAR census of non-recycled pulsars sample
- Short Name:
- J/A+A/635/A75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from the low-frequency (40-78MHz) extension of the first pulsar census of non-recycled pulsars carried out with the LOw-Frequency ARray (LOFAR). We used the low-band antennas of the LOFAR core stations to observe 87 pulsars out of 158 that had been previously detected using high-band antennas. We present flux densities and flux-calibrated profiles for the 43 pulsars we detected. Of this sample, 17 have not, to our knowledge, previously been detected at such low frequencies. Here we recalculate the spectral indices using the new low-frequency flux density measurements from the LOFAR census and discuss the prospects of studying pulsars at very low frequencies using current and upcoming facilities, such as the New Extension in Nancay Upgrading LOFAR (NenuFAR).
- ID:
- ivo://CDS.VizieR/J/A+A/583/A137
- Title:
- LOFAR-HBA 3C196 field RM cubes
- Short Name:
- J/A+A/583/A137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study aims to characterize linear polarization structures in LOFAR observations of the interstellar medium (ISM) in the 3C196 field, one of the primary fields of the LOFAR-Epoch of Reionization key science project. We have used the high band antennas (HBA) of LOFAR to image this region and Rotation Measure (RM) synthesis to unravel the distribution of polarized structures in Faraday depth. The brightness temperature of the detected Galactic emission is 5-15K in polarized intensity and covers the range from -3 to +8 rad/m^2^ in Faraday depth. The most interesting morphological feature is a strikingly straight filament at a Faraday depth of +0.5 rad/m^2^ running from north to south, right through the centre of the field and parallel to the Galactic plane. There is also an interesting system of linear depolarization canals conspicuous in an image showing the peaks of Faraday spectra. We used the Westerbork Synthesis Radio Telescope (WSRT) at 350MHz to image the same region. For the first time, we see some common morphology in the RM cubes made at 150 and 350MHz. There is no indication of diffuse emission in total intensity in the interferometric data, in line with results at higher frequencies and previous LOFAR observations. Based on our results, we determined physical parameters of the ISM and proposed a simple model that may explain the observed distribution of the intervening magneto-ionic medium. The mean line-of-sight magnetic field component is determined to be 0.3-/+0.1uG and its spatial variation across the 3C196 field is 0.1uG. The filamentary structure is probably an ionized filament in the ISM, located somewhere within the Local Bubble. This filamentary structure shows an excess in thermal electron density (n_e_*B_||_>6.2cm^-3^uG) compared to its surroundings.
- ID:
- ivo://CDS.VizieR/J/AJ/152/36
- Title:
- Low-mass star-forming cores observed with SHARC-II
- Short Name:
- J/AJ/152/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of low-mass dense cores observed with the SHARC-II instrument at 350{mu}m. Our observations have an effective angular resolution of 10'', approximately 2.5 times higher than observations at the same wavelength obtained with the Herschel Space Observatory, albeit with lower sensitivity, especially to extended emission. The catalog includes 81 maps covering a total of 164 detected sources. For each detected source, we tabulate basic source properties including position, peak intensity, flux density in fixed apertures, and radius. We examine the uncertainties in the pointing model applied to all SHARC-II data and conservatively find that the model corrections are good to within ~3'', approximately 1/3 of the SHARC-II beam. We examine the differences between two array scan modes and find that the instrument calibration, beam size, and beam shape are similar between the two modes. We also show that the same flux densities are measured when sources are observed in the two different modes, indicating that there are no systematic effects introduced into our catalog by utilizing two different scan patterns during the course of taking observations. We find a detection rate of 95% for protostellar cores but only 45% for starless cores, and demonstrate the existence of a SHARC-II detection bias against all but the most massive and compact starless cores. Finally, we discuss the improvements in protostellar classification enabled by these 350{mu}m observations.
- ID:
- ivo://CDS.VizieR/J/PASJ/65/119
- Title:
- Low-resolution NIR spectra of zodiacal light
- Short Name:
- J/PASJ/65/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the 278 low-resolution (R~20) near-infrared (1.8-5.3micron) spectra of diffuse sky covering a wide range of galactic and ecliptic latitudes with the Infrared Camera (IRC) on board AKARI before the exhaustion of liquid-helium (from September 2006 to May 2007). Advanced reduction methods specialized for the slit spectroscopy of diffuse sky spectra are developed for constructing this spectral catalog. Filter wheel of the IRC instrument has dark position to measure the dark current, and uncertainty due to dark current subtraction is estimated to be <3nW/m2/sr at 2micron (Tsumura & Wada, 2011PASJ...63..755T). Point sources brighter than mK(Vega)=19 were detected on the slit and masked for deriving the diffuse spectrum. It was confirmed that the brightness due to unresolved galactic stars under this detection limit is negligible (<0.5% of the sky brightness at 2.2 micron) by a Milky Way star count model (TRILEGAL; Girardi et al., 2005A&A...436..895G). Cumulative brightness contributed by unresolved galaxies can be estimated by the deep galaxy counts, being <4nW/m2/sr at K band in the case of limiting magnitude of mK=19 (Keenan et al., 2010ApJ...723...40K).
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A6
- Title:
- Ly{alpha}-[CII] velocity offsets in MS galaxies
- Short Name:
- J/A+A/643/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Lyman-{alpha} line in the ultraviolet (UV) and the [CII] line in the far-infrared (FIR) are widely used tools to identify galaxies in the early Universe and to obtain insights into interstellar medium (ISM) properties in high-redshift galaxies. By combining data obtained with ALMA in band 7 at ~320GHz as part of the ALMA Large Program to INvestigate [CII] at Early Times (ALPINE) with spectroscopic data from DEIMOS at the Keck Observatory, VIMOS and FORS2 at the Very Large Telescope, we assembled a unique sample of 53 main-sequence star-forming galaxies at 4.4<z<6 in which we detect both the Lyman-{alpha} line in the UV and the [CII] line in the FIR. The goal of this paper is to constrain the properties of the Ly{alpha} emission in these galaxies in relation to other properties of the ISM. We used [CII], observed with ALMA, as a tracer of the systemic velocity of the galaxies, and we exploited the available optical spectroscopy to obtain the Ly{alpha}-[CII] and ISM-[CII] velocity offsets. We find that 90% of the selected objects have Ly{alpha}-[CII] velocity offsets in the range 0<{Delta}v_Ly{alpha}-[CII]_<400km/s, in line with the few measurements available so far in the early Universe, and significantly smaller than those observed at lower redshifts. At the same time, we observe ISM-[CII] offsets in the range -500<{Delta}v_ISM-[CII]_<0km/s, in line with values at all redshifts, which we interpret as evidence for outflows in these galaxies. We find significant anticorrelations between {Delta}v_Ly{alpha}-[CII]_ and the Ly{alpha} rest-frame equivalent width EW_0_(Ly{alpha}) (or equivalently, the Ly{alpha} escape fraction f_esc_(Ly{alpha})): galaxies that show smaller {Delta}v_Ly{alpha}-[CII]_ have larger EW_0_(Ly{alpha}) and f_esc_(Ly{alpha}). We interpret these results in the framework of available models for the radiative transfer of Ly{alpha} photons. According to the models, the escape of Ly{alpha} photons would be favored in galaxies with high outflow velocities, producing large EW_0_(Ly{alpha}) and small {Delta}v_Ly{alpha}-[CII]_, in agreement with our observations. The uniform shell model would also predict that the Ly{alpha} escape in galaxies with slow outflows (0<v_out_<300km/s) is mainly determined by the neutral hydrogen column density (NHI) along the line of sight, while the alternative model by Steidel et al. (2010ApJ...717..289S) would more highly favor a combination of NHI at the systemic velocity and covering fraction as driver of the Ly{alpha} escape. We suggest that the increase in Ly{alpha} escape that is observed in the literature between z~2 and z~6 is not due to a higher incidence of fast outflows at high redshift, but rather to a decrease in average NHI along the line of sight, or alternatively, a decrease in HI covering fraction.
- 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.
