- ID:
- ivo://CDS.VizieR/J/A+A/634/A47
- Title:
- Planetary nebula NGC3132 MUSE images
- Short Name:
- J/A+A/634/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two-dimensional spectroscopic data for the whole extent of the NGC3132 planetary nebula have been obtained. We deliver a reduced data-cube and high-quality maps on a spaxel-by-spaxel basis for the many emission lines falling within the Multi-Unit Spectroscopic Explorer (MUSE) spectral coverage over a range in surface brightness >1000. Physical diagnostics derived from the emission line images, opening up a variety of scientific applications, are discussed. Data were obtained during MUSE commissioning on the European Southern Observatory (ESO) Very Large Telescope and reduced with the standard ESO pipeline. Emission lines were fitted by Gaussian profiles. The dust extinction, electron densities, and temperatures of the ionised gas and abundances were determined using Python and PyNeb routines. The delivered datacube has a spatial size of ~63"x123", corresponding to ~0.26x0.51pc^2^ for the adopted distance, and a contiguous wavelength coverage of 4750-9300{AA} at a spectral sampling of 1.25{AA}/pix. The nebula presents a complex reddening structure with high values (c(H{beta})~0.4) at the rim. Density maps are compatible with an inner high-ionisation plasma at moderate high density (~1000cm^-3^), while the low-ionisation plasma presents a structure in density peaking at the rim with values ~700cm^-3^. Median Te, using different diagnostics, decreases according to the sequence [NII],[SII]->[SIII]->[OI]->HeI->Paschen Jump. Likewise, the range of temperatures covered by recombination lines is much larger than those obtained from collisionally excited lines (CELs), with large spatial variations within the nebula. If these differences were due to the existence of high density clumps, as previously suggested, these spatial variations would suggest changes in the properties and/or distribution of the clumps within the nebula. We determined a median helium abundance He/H=0.124, with slightly higher values at the rim and outer shell. The range of measured ionic abundances for light elements are compatible with literature values. Our kinematic analysis nicely illustrates the power of 2D kinematic information in many emission lines, which sheds light on the intrinsic structure of the nebula. Specifically, our derived velocity maps support a geometry for the nebula that is similar to the diabolo-like model previously proposed, but oriented with its major axis roughly at P.A.~22{deg}. We identified two low-surface brightness arc-like structures towards the northern and southern tips of the nebula, with high extinction, high helium abundance, and strong low-ionisation emission lines. They are spatially coincident with some extended low-surface brightness mid-infrared emission. The characteristics of the features suggest that they could be the consequence of precessing jets caused by the binary star system. A simple 1D Cloudy model is able to reproduce the strong lines in the integrated spectrum of the whole nebula with an accuracy of 15% . Together with similar work with MUSE on NGC7009, the present study illustrates the enormous potential of wide field integral field spectrographs for the study of Galactic PNe.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/155/21
- Title:
- Planet candidates from K2 campaigns 5-8
- Short Name:
- J/AJ/155/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 151 planet candidates orbiting 141 stars from K2 campaigns 5-8 (C5-C8), identified through a systematic search of K2 photometry. In addition, we identify 16 targets as likely eclipsing binaries, based on their light curve morphology. We obtained follow-up optical spectra of 105/141 candidate host stars and 8/16 eclipsing binaries to improve stellar properties and to identify spectroscopic binaries. Importantly, spectroscopy enables measurements of host star radii with ~10% precision, compared to ~40% precision when only broadband photometry is available. The improved stellar radii enable improved planet radii. Our curated catalog of planet candidates provides a starting point for future efforts to confirm and characterize K2 discoveries.
- ID:
- ivo://CDS.VizieR/J/AJ/153/136
- Title:
- Planets and their host stars with Gaia parallaxes
- Short Name:
- J/AJ/153/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present empirical measurements of the radii of 116 stars that host transiting planets. These radii are determined using only direct observables - the bolometric flux at Earth, the effective temperature, and the parallax provided by the Gaia first data release - and thus are virtually model independent, with extinction being the only free parameter. We also determine each star's mass using our newly determined radius and the stellar density, a virtually model independent quantity itself from previously published transit analyses. These stellar radii and masses are in turn used to redetermine the transiting-planet radii and masses, again using only direct observables. The median uncertainties on the stellar radii and masses are 8% and 30%, respectively, and the resulting uncertainties on the planet radii and masses are 9% and 22%, respectively. These accuracies are generally larger than previously published model-dependent precisions of 5% and 6% on the planet radii and masses, respectively, but the newly determined values are purely empirical. We additionally report radii for 242 stars hosting radial-velocity (non-transiting) planets, with a median achieved accuracy of ~2%. Using our empirical stellar masses we verify that the majority of putative "retired A stars" in the sample are indeed more massive than ~1.2 M_{sun}_. Most importantly, the bolometric fluxes and angular radii reported here for a total of 498 planet host stars-with median accuracies of 1.7% and 1.8%, respectively-serve as a fundamental data set to permit the re-determination of transiting-planet radii and masses with the Gaia second data release to ~3% and ~5% accuracy, better than currently published precisions, and determined in an entirely empirical fashion.
- ID:
- ivo://CDS.VizieR/J/ApJ/697/544
- Title:
- Planets orbiting metal-poor dwarfs. II.
- Short Name:
- J/ApJ/697/544
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of three years of precision radial velocity (RV) measurements of 160 metal-poor stars observed with HIRES on the Keck 1 telescope. We report on variability and long-term velocity trends for each star in our sample. We identify several long-term, low-amplitude RV variables worthy of followup with direct imaging techniques. We place lower limits on the detectable companion mass as a function of orbital period. Our survey would have detected, with a 99.5% confidence level, over 95% of all companions on low-eccentricity orbits with velocity semiamplitude K>~100m/s, or M_p_sini>~3.0M_J_(P/yr)^(1/3)^, for orbital periods P<~3yr. None of the stars in our sample exhibits RV variations compatible with the presence of Jovian planets with periods shorter than the survey duration.
- ID:
- ivo://CDS.VizieR/J/ApJ/855/107
- Title:
- PMAS Integral-field SN hosts COmpilation (PISCO)
- Short Name:
- J/ApJ/855/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the PMAS/PPak Integral-field Supernova hosts COmpilation (PISCO), which comprises integral field spectroscopy (IFS) of 232 supernova (SN) host galaxies that hosted 272 SNe, observed over several semesters with the 3.5m telescope at the Calar Alto Observatory (CAHA). PISCO is the largest collection of SN host galaxies observed with wide-field IFS, totaling 466347 individual spectra covering a typical spatial resolution of ~380pc. Focused studies regarding specific SN Ia-related topics will be published elsewhere; this paper aims to present the properties of the SN environments, using stellar population (SP) synthesis, and the gas-phase interstellar medium, providing additional results separating stripped-envelope SNe into their subtypes. With 11270 HII regions detected in all galaxies, we present for the first time a statistical analysis of HII regions, which puts HII regions that have hosted SNe in context with all other star-forming clumps within their galaxies. SNe Ic are associated with environments that are more metal-rich and have higher EW(H{alpha}) and higher star formation rate within their host galaxies than the mean of all HII regions detected within each host. This in contrast to SNe IIb, which occur in environments that are very different compared to other core-collapse SNe types. We find two clear components of young and old SPs at SNe IIn locations. We find that SNe II fast decliners tend to explode at locations where the {Sigma}SFR is more intense. Finally, we outline how a future dedicated IFS survey of galaxies in parallel to an untargeted SN search would overcome the biases in current environmental studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/762/77
- Title:
- PM2GC mass-limited sample surface photometry
- Short Name:
- J/ApJ/762/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search for massive and compact galaxies (superdense galaxies, hereafter SDGs) at z=0.03-0.11 in the Padova-Millennium Galaxy and Group Catalogue (PM2GC), a spectroscopically complete sample representative of the general field population of the local universe. We find that compact galaxies with radii and mass densities comparable to high-z massive and passive galaxies represent 4.4% of all galaxies with stellar masses above 3x10^10^M_{sun}_, yielding a number density of 4.3x10^-4^h^3^/Mpc^3^. Most of them are S0s (70%) or ellipticals (23%), are red, and have intermediate-to-old stellar populations, with a median luminosity-weighted age of 5.4Gyr and a median mass-weighted age of 9.2Gyr. Their velocity dispersions and dynamical masses are consistent with the small radii and high stellar mass estimates. Comparing with the WINGS sample of cluster galaxies at similar redshifts, the fraction of SDGs is three times smaller in the field than in clusters, and cluster SDGs are on average 4Gyr older than field SDGs. We confirm the existence of a universal trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass. As a consequence, the median mass-size relation shifts toward smaller radii for galaxies with older stars, but the effect is much more pronounced in clusters than in the field. Our results show that, on top of the well-known dependence of stellar age on galaxy mass, the luminosity-weighted age of galaxies depends on galaxy compactness at fixed mass and, for a fixed mass and radius, on environment. This effect needs to be taken into account in order not to overestimate the evolution of galaxy sizes from high to low z. Our results and hierarchical simulations suggest that a significant fraction of the massive compact galaxies at high z have evolved into compact galaxies in galaxy clusters today. When stellar age and environmental effects are taken into account, the average amount of size evolution of individual galaxies between high and low z is mild, a factor ~1.6.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A106
- Title:
- p-mode frequencies of the solar twin 18 Sco
- Short Name:
- J/A+A/544/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Solar twins have been a focus of attention for more than a decade, because their structure is extremely close to that of the Sun. Today, thanks to high-precision spectrometers, it is possible to use asteroseismology to probe their interiors. Our goal is to use time series obtained from the HARPS spectrometer to extract the oscillation frequencies of 18 Sco, the brightest solar twin. We used the tools of spectral analysis to estimate these quantities. We estimate 52 frequencies using a Markov Chain Monte-Carlo (MCMC) algorithm. After examination of their probability densities and comparison with results from direct MAP optimization, we obtain a minimal set of 21 reliable modes. The identification of each pulsation mode is straightforwardly accomplished by comparing to the well-established solar pulsation modes. We also derived some basic seismic indicators using these values. These results offer a good basis to start a detailed seismic analysis of 18 Sco using stellar models.
- ID:
- ivo://CDS.VizieR/J/ApJS/185/451
- Title:
- PMS stars in the Cepheus flare region
- Short Name:
- J/ApJS/185/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of optical spectroscopic and BVR_C_I_C_ photometric observations of 77 pre-main-sequence (PMS) stars in the Cepheus flare region. A total of 64 of these are newly confirmed PMS stars, originally selected from various published candidate lists. We estimate effective temperatures and luminosities for the PMS stars, and comparing the results with PMS evolutionary models, we estimate stellar masses of 0.2-2.4M_{sun}_ and stellar ages of 0.1-15Myr. Among the PMS stars, we identify 15 visual binaries with separations of 2-10". From archival IRAS, Two Micron All Sky Survey, and Spitzer data, we construct their spectral energy distributions (SEDs) and classify 5% of the stars as Class I, 10% as Flat SED, 60% as Class II, and 3% as Class III young stellar objects. We identify 12 classical T Tauri stars and two weak-line T Tauri stars as members of NGC 7023, with a mean age of 1.6Myr. The 13 PMS stars associated with L1228 belong to three small aggregates: RNO 129, L1228A, and L1228S. The age distribution of the 17 PMS stars associated with L1251 suggests that star formation has propagated with the expansion of the Cepheus flare shell. We detect sparse aggregates of ~6-7Myr old PMS stars around the dark clouds L1177 and L1219, at a distance of ~400pc. Three T Tauri stars appear to be associated with the Herbig Ae star SV Cep at a distance of 600pc. Our results confirm that the molecular complex in the Cepheus flare region contains clouds of various distances and star-forming histories.
- ID:
- ivo://CDS.VizieR/J/A+A/495/447
- Title:
- PN and HII regions in NGC6822
- Short Name:
- J/A+A/495/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Images obtained with the CTIO 4-m telescope and the MOSAIC-2 wide field camera in [OIII] 5007 and Halpha on-band and off-band filters are analyzed to search for emission line objects in the dwarf galaxy NGC 6822. In particular we search for planetary nebula (PN) candidates. In addition, imaging and spectroscopy of a sub-sample of objects obtained with the ESO VLT and FORS 2 spectrograph are used to calibrate the MOSAIC imaging. In the continuum-subtracted images, a large number of line emission regions were detected, for which we measured instrumental magnitudes in all the filters. The [OIII] 5007 and Halpha+[NII] magnitudes were calibrated with the spectroscopy.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/3443
- Title:
- PNe and HII regions plasma diagnostics
- Short Name:
- J/MNRAS/428/3443
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carry out plasma diagnostic analyses for 123 planetary nebulae (PNe) and 42 HII regions using the NII and OII optical recombination lines (ORLs). New effective recombination coefficients for the NII and OII optical recombination spectra are used. These data were calculated under the intermediate coupling scheme for a number of electron temperature (Te) and density (Ne) cases. We use a new method to determine the Te's and Ne's for the nebular sample, combining the ORLs with the most reliable measurements for each ion and the predicted intensities that are based on the new atomic data. Uncertainties of the derived Te and Ne are estimated for each object. The diagnostic results from heavy element ORLs show reasonable agreement with previous calculations in the literature. We compare the electron temperatures derived from the NII and OII ORLs, Te(ORLs), and those from the collisionally excited lines (CELs), Te(CELs), as well as the hydrogen Balmer jump, Te(HIBJ), especially for the PNe with large abundance discrepancies. Temperatures from the HeI recombination lines, Te(HeI), are also used for comparison if available. For all the objects included in our sample, Te(ORLs) are lower than Te(HIBJ), which are in turn systematically lower than Te(CELs). PNe with Te(HeI) available show the relation Te(ORLs)<=Te(HeI)<=Te(HIBJ)<=Te(CELs), which is consistent with predictions from the bi-abundance nebular model postulated by Liu et al. (2000MNRAS.312..585L).
