- ID:
- ivo://CDS.VizieR/J/MNRAS/415/181
- Title:
- Deep spectroscopy of NGC 7009
- Short Name:
- J/MNRAS/415/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present very deep CCD spectrum of the bright, medium-excitation planetary nebula NGC 7009, with a wavelength coverage from 3040 to 11000{AA}. Traditional emission line identification is carried out to identify all the emission features in the spectra, based on the available laboratory atomic transition data. Since the spectra are of medium resolution, we use multi-Gaussian line profile fitting to deblend faint blended lines, most of which are optical recombination lines (ORLs) emitted by singly ionized ions of abundant second-row elements such as C, N, O and Ne.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/799/148
- Title:
- DEIMOS galaxy sample at z~0.7
- Short Name:
- J/ApJ/799/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Scaling relations between galaxy structures and dynamics have been studied extensively for early- and late-type galaxies, both in the local universe and at high redshifts. The abundant differences between the properties of disky and elliptical, or star-forming and quiescent, galaxies seem to be characteristic of the local universe; such clear distinctions begin to disintegrate as observations of massive galaxies probe higher redshifts. In this paper we investigate the existence of the mass fundamental plane of all massive galaxies ({sigma}>~100km/s). This work includes local galaxies (0.05<z<0.07) from the Sloan Digital Sky Survey, in addition to 31 star-forming and 72 quiescent massive galaxies at intermediate redshift (z~0.7) with absorption-line kinematics from deep Keck-DEIMOS spectra and structural parameters from Hubble Space Telescope imaging. In two-parameter scaling relations, star-forming and quiescent galaxies differ structurally and dynamically. However, we show that massive star-forming and quiescent galaxies lie on nearly the same mass fundamental plane, or the relationship between stellar mass surface density, stellar velocity dispersion, and effective radius. The scatter in this relation (measured about log{sigma}) is low: 0.072dex (0.055dex intrinsic) at z~0 and 0.10dex (0.08dex intrinsic) at z~0.7. This 3D surface is not unique: virial relations, with or without a dependence on luminosity profile shapes, can connect galaxy structures and stellar dynamics with similar scatter. This result builds on the recent finding that mass fundamental plane has been stable for early-type galaxies since z~2. As we now find that this also holds for star-forming galaxies to z~0.7, this implies that these scaling relations of galaxies will be minimally susceptible to progenitor biases owing to the evolving stellar populations, structures, and dynamics of galaxies through cosmic time.
- ID:
- ivo://CDS.VizieR/J/ApJ/858/77
- Title:
- DEIMOS 10K spectroscopic survey in COSMOS field
- Short Name:
- J/ApJ/858/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 10718 objects in the COSMOS field, observed through multi-slit spectroscopy with the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II telescope in the wavelength range ~5500-9800{AA}. The catalog contains 6617 objects with high-quality spectra (two or more spectral features), and 1798 objects with a single spectroscopic feature confirmed by the photometric redshift. For 2024 typically faint objects, we could not obtain reliable redshifts. The objects have been selected from a variety of input catalogs based on multi-wavelength observations in the field, and thus have a diverse selection function, which enables the study of the diversity in the galaxy population. The magnitude distribution of our objects is peaked at I_AB_~23 and K_AB_~21, with a secondary peak at K_AB_~24. We sample a broad redshift distribution in the range 0<z<6, with one peak at z~1, and another one around z~4. We have identified 13 redshift spikes at z>0.65 with chance probabilities <4x10^-4^, some of which are clearly related to protocluster structures of sizes >10Mpc. An object-to-object comparison with a multitude of other spectroscopic samples in the same field shows that our DEIMOS sample is among the best in terms of fraction of spectroscopic failures and relative redshift accuracy. We have determined the fraction of spectroscopic blends to about 0.8% in our sample. This is likely a lower limit and at any rate well below the most pessimistic expectations. Interestingly, we find evidence for strong lensing of Ly{alpha} background emitters within the slits of 12 of our target galaxies, increasing their apparent density by about a factor of 4.
554. 1 Del spectroscopy
- ID:
- ivo://CDS.VizieR/J/A+A/587/A22
- Title:
- 1 Del spectroscopy
- Short Name:
- J/A+A/587/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stable shell stars are ideal objects for studying basic physical principles of the formation of disks in Be stars. If these stars have a close unresolved visual companion, its contribution toward the modelling of the disk cannot be overlooked, as is sometimes done. The study aims to spectroscopically resolve close visual binary Be (shell) star 1 Del, which up to now was only resolved by speckle or micrometric measurements. The integral field spectroscopy obtained by the SINFONI spectrograph at the VLT telescope in the European Southern Observatory (ESO) in the infrared region was used; we supplemented these observations with visual spectroscopy with the Perek Telescope at the Ondrejov Observatory. Spectra of 1 Del were successfully resolved, and, for the first time, spectra of 1 Del B were obtained. We found that 1 Del A is a Be/shell star, while 1 Del B is not an emission-line object.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A73
- Title:
- delta Cep HARPS-N radial velocities
- Short Name:
- J/A+A/597/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The projection factor p is the key quantity used in the Baade-Wesselink (BW) method for distance determination; it converts radial velocities into pulsation velocities. Several methods are used to determine p, such as geometrical and hydrodynamical models or the inverse BW approach when the distance is known. We analyze new HARPS-N spectra of delta Cep to measure its cycle-averaged atmospheric velocity gradient in order to better constrain the projection factor. We first apply the inverse BW method to derive p directly from observations. The projection factor can be divided into three subconcepts: (1) a geometrical effect (p_0_), (2) the velocity gradient within the atmosphere (f_grad_), and (3) the relative motion of the optical pulsating photosphere with respect to the corresponding mass elements (f_o_-g). We then measure the fgrad value of delta Cep for the first time. When the HARPS-N mean cross-correlated line-profiles are fitted with a Gaussian profile, the projection factor is p_cc-g_=1.239+/-0.034(stat.)+/-0.023 (syst.). When we consider the different amplitudes of the radial velocity curves that are associated with 17 selected spectral lines, we measure projection factors ranging from 1.273 to 1.329. We find a relation between fgrad and the line depth measured when the Cepheid is at minimum radius. This relation is consistent with that obtained from our best hydrodynamical model of delta Cep and with our projection factor decomposition. Using the observational values of p and f_grad_ found for the 17 spectral lines, we derive a semi-theoretical value of f_o-g_. We alternatively obtain f_o-g_=0.975+/-0.002 or 1.006+/-0.002 assuming models using radiative transfer in plane-parallel or spherically symmetric geometries, respectively. The new HARPS-N observations of delta Cep are consistent with our decomposition of the projection factor. The next step will be to measure p0 directly from the next generation of visible interferometers. With these values in hand, it will be possible to derive fo-g directly from observations.
556. Delta Scuti stars
- ID:
- ivo://CDS.VizieR/J/A+AS/144/469
- Title:
- Delta Scuti stars
- Short Name:
- J/A+AS/144/469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive and up-dated list of {delta} Sct stars is presented here. More than 500 papers, published during the last few years, have been revised and 341 new variables have been added to our last list, six years ago. This catalogue is intended to be a comprehensive review on the observational characteristics of all the {delta} Sct stars known until now, including stars contained in earlier catalogues together with other new discovered variables, covering information published until January 2000. In summary, 636 variables, 1149 references and 182 individual notes are presented in this new list.
- ID:
- ivo://CDS.VizieR/J/A+A/288/601
- Title:
- Dense molecular cores
- Short Name:
- J/A+A/288/601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/other/ChA+A/36.238
- Title:
- Dense parts of outflows toward massive cores
- Short Name:
- J/other/ChA+A/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A set of samples of 13 massive star-forming cores were observed in SiO (2-1), CH_3_OH (2-1) and C^34^S (2-1) thermal lines. Nine of these cores were detected in all three lines. Among the nine SiO detections, three were new detections, and relatively faint. Most of the lines have wide wings, which might be interpreted as the evidence of ongoing energetic outflows in the cores.
- ID:
- ivo://CDS.VizieR/J/A+A/651/A59
- Title:
- Dense warm ionized medium in the inner Galaxy
- Short Name:
- J/A+A/651/A59
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Ionized interstellar gas is an important component of the interstellar medium and its lifecycle. The recent evidence for a widely distributed highly ionized warm interstellar gas with a density intermediate between the warm ionized medium (WIM) and compact HII regions suggests that there is a major gap in our understanding of the interstellar gas. Our goal is to investigate the properties of the dense warm ionized medium in the Milky Way using spectrally resolved SOFIA GREAT [NII] 205um fine-structure lines and Green Bank Telescope hydrogen radio recombination lines (RRL) data, supplemented by spectrally unresolved Herschel PACS [NII] 122um data, and spectrally resolved ^12^CO. We observed eight lines of sight (LOS) in the 20{deg}<l<30{deg}region in the Galactic plane. We spectrally unresolved Herschel PACS [NII] 122um data, and spectrally resolved ^12^CO. Methods. We observed eight lines of sight (LOS) in the 20{deg}<l<30{deg}region in the Galactic plane. We analyzed spectrally resolved lines of [NII] at 205um and RRL observations, along with the spectrally unresolved Herschel PACS 122um emission, using excitation and radiative transfer models to determine the physical parameters of the dense warm ionized medium. We derived the kinetic temperature, as well as the thermal and turbulent velocity dispersions from the [NII] and RRL linewidths. The regions with [NII] 205um emission are characterized by electron densities, n(e)~10-35cm^-3^, temperatures range from 3400 to 8500K, and nitrogen column densities N(N^+^)~7x10^16^ to 3x10^17^cm^-2^. The ionized hydrogen column densities range from 6x10^20^ to 1.7x10^21^cm^-2^ and the fractional nitrogen ion abundance x(N^+^)~1.1x10^-4^ to 3.0x10^-4^, implying an enhanced nitrogen abundance at a distance ~4.3kpc from the Galactic Center. The [NII] 205um emission lines coincide with CO emission, although often with an offset in velocity, which suggests that the dense warm ionized gas is located in, or near, star-forming regions, which themselves are associated with molecular gas. These dense ionized regions are found to contribute >~50% of the observed [CII] intensity along these LOS. The kinetic temperatures we derive are too low to explain the presence of N^+^ resulting from electron collisional ionization and/or proton charge transfer of atomic nitrogen. Rather, these regions most likely are ionized by extreme ultraviolet (EUV) radiation from nearby star-forming regions or as a result of EUV leakage through a clumpy and porous interstellar medium.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A42
- Title:
- Detected CH_2_ spectra
- Short Name:
- J/A+A/647/A42
- Date:
- 19 Jan 2022 13:29:47
- Publisher:
- CDS
- Description:
- The N_KaKc_=4_04_-3_13_ transitions of ortho-CH_2_ between 68 and 71GHz were first detected toward the Orion-KL and W51 Main star-forming regions. Given their high upper level energies (225K) above the ground state, they were naturally thought to arise in dense, hot molecular cores near newly formed stars. However, this has not been confirmed by further observations of these lines and their origin has remained unclear. Quite in general, only a paucity of observational data exist for CH_2_ and, while astrochemically an important compound, its actual occurrence in astronomical sources is poorly constrained. In this work, we aim to investigate the nature of the elusive CH_2_ emission and address its association with hot cores and examine alternative possibilities for its origin. Owing to its importance in carbon chemistry, we also extend the search for CH_2_ lines by observing an assortment of regions guided by the hypothesis that the observed CH_2_ emission likely arises from the hot gas environment of photodissociation regions (PDRs). We carried out observations using, first, the Kitt Peak 12m telescope to verify the original detection of CH_2_ toward different positions in the central region of Orion Molecular Cloud 1. These were followed-up by deep integrations using the higher angular resolution of the Onsala 20 m telescope. We have also searched for the N_KaKc_=2_12_-3_03_ transitions of para-CH_2_ between 440-445GHz toward the Orion giant molecular cloud complex using the APEX 12m telescope. We also obtained auxiliary data for carbon recombination lines with the Effelsberg 100m telescope and employed archival far infrared data. Our and other recent observations of the Orion region reported here, rule out an association with hot and dense gas. We find that the distribution of the CH_2_ emission follows closely that of the [CII] 158 um emission while CH_2_ is undetected toward the hot core itself. The observations suggest that its extended emission rather arises from hot but dilute layers of PDRs, but not from the denser parts of such regions, in particular the Orion Bar. This hypothesis was corroborated by comparisons of the observed CH_2_ line profiles with those of carbon radio recombination lines (CRRLs), well known PDR tracers. In addition, we report the detection of the 70GHz fine-, and hyperfine structure components of ortho-CH_2_ toward the W51 E, W51 M, W51 N, W49 N, W43, W75 N, DR21, and S140 star-forming regions, and three of the N_KaKc_=4_04_-3_13_ fine- and hyperfine structure transitions between 68-71GHz toward W3 IRS5. While we have no information on CH_2_'s spatial distribution in these regions, except for W51, we again see a correspondence of the profiles of CH_2_ lines with those of CRRLs. We see stronger CH_2_ emission toward the extended HII region W51 M than toward the much more massive and denser W51 E and N regions, strongly supporting an origin of CH_2_ in extended dilute gas. We also report the non-detection of the 2_12_-3_03_ transitions of para-CH_2_ toward Orion. Furthermore, using a non-LTE radiative transfer analysis, we can constrain the gas temperatures and H_2_ density to (163+/-26)K and (3.4+/-0.3)x10^3^cm^-3^, respectively, for the 68-71GHz ortho-CH_2_ transitions toward W3 IRS5, for which we have the highest quality data set. This analysis confirms our hypothesis that CH_2_ originates in warm and dilute PDR layers. Our analysis suggests that for the excitation conditions under the physical conditions that prevail in such an environment, these lines are masering, with weak level inversion. The resulting amplification of the lines' spontaneous emission greatly aides their detection.
