- ID:
- ivo://CDS.VizieR/J/ApJ/887/105
- Title:
- Herschel/SPIRE FTS [CI] lines in KINGFISH gal.
- Short Name:
- J/ApJ/887/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present resolved [CI] line intensities of 18 nearby galaxies observed with the SPIRE FTS spectrometer on the Herschel Space Observatory. We use these data along with resolved CO line intensities from J_up_=1 to 7 to interpret what phase of the interstellar medium the [CI] lines trace within typical local galaxies. A tight, linear relation is found between the intensities of the CO(4-3) and [CI](2-1) lines; we hypothesize this is due to the similar upper level temperature of these two lines. We modeled the [CI] and CO line emission using large-velocity gradient models combined with an empirical template. According to this modeling, the [CI](1-0) line is clearly dominated by the low-excitation component. We determine [CI] to molecular mass conversion factors for both the [CI](1-0) and [CI](2-1) lines, with mean values of {alpha}_[CI](1-0)_=7.3M_{sun}_/K/km.s/pc^2^ and {alpha}_[CI](2-1)_=34M_{sun}_/K/km.s/pc^2^ with logarithmic root-mean-square spreads of 0.20 and 0.32dex, respectively. The similar spread of {alpha}_[CI](1-0)_ to {alpha}_CO_ (derived using the CO(2-1) line) suggests that [CI](1-0) may be just as good a tracer of cold molecular gas as CO(2-1) in galaxies of this type. On the other hand, the wider spread of {alpha}_[CI](2-1)_ and the tight relation found between [CI](2-1) and CO(4-3) suggest that much of the [CI](2-1) emission may originate in warmer molecular gas.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/230/1
- Title:
- Herschel SPIRE/FTS 194-671um survey of GOALS LIRGs
- Short Name:
- J/ApJS/230/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a Herschel Space Observatory 194-671{mu}m spectroscopic survey of a sample of 121 local luminous infrared galaxies and report the fluxes of the CO J to J-1 rotational transitions for 4<=J<=13, the [NII] 205{mu}m line, the [CI] lines at 609 and 370{mu}m, as well as additional and usually fainter lines. The CO spectral line energy distributions (SLEDs) presented here are consistent with our earlier work, which was based on a smaller sample, that calls for two distinct molecular gas components in general: (i) a cold component, which emits CO lines primarily at J<~4 and likely represents the same gas phase traced by CO (1-0), and (ii) a warm component, which dominates over the mid-J regime (4<J<~10) and is intimately related to current star formation. We present evidence that the CO line emission associated with an active galactic nucleus is significant only at J>10. The flux ratios of the two [CI] lines imply modest excitation temperatures of 15-30K; the [CI] 370{mu}m line scales more linearly in flux with CO (4-3) than with CO (7-6). These findings suggest that the [CI] emission is predominantly associated with the gas component defined in (i) above. Our analysis of the stacked spectra in different far-infrared (FIR) color bins reveals an evolution of the SLED of the rotational transitions of H_2_O vapor as a function of the FIR color in a direction consistent with infrared photon pumping.
- ID:
- ivo://CDS.VizieR/J/A+A/568/A90
- Title:
- Herschel/SPIRE spectra in Arp 299
- Short Name:
- J/A+A/568/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Ultra) luminous infrared galaxies ((U)LIRGs) are nearby laboratories that allow us to study similar processes to those occurring in high redshift submillimeter galaxies. Understanding the heating and cooling mechanisms in these galaxies can give us insight into the driving mechanisms in their more distant counterparts. Molecular emission lines play a crucial role in cooling excited gas, and recently, with Herschel Space Observatory we have been able to observe the rich molecular spectrum. Carbon monoxide (CO) is the most abundant and one of the brightest molecules in the Herschel wavelength range. CO transitions from J=4-3 to 13-12 are observed with Herschel, and together, these lines trace the excitation of CO. We study Arp 299, a colliding galaxy group, with one component (A) harboring an active galactic nucleus and two more (B and C) undergoing intense star formation. For Arp 299 A, we present PACS spectrometer observations of high-J CO lines up to J=20-19 and JCMT observations of ^13^CO and HCN to discern between UV heating and alternative heating mechanisms.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/31
- Title:
- HETDEX pilot survey. II. 1.9<z<3.8 LAEs
- Short Name:
- J/ApJ/736/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the escape of Ly{alpha} photons from Ly{alpha} emitting galaxies (LAEs) and the overall galaxy population using a sample of 99 LAEs at 1.9<z<3.8 detected through integral-field spectroscopy of blank fields by The Hobby Eberly Telescope Dark Energy Experiment Pilot Survey. For 89 LAEs with broadband counterparts we measure ultraviolet (UV) luminosities and UV slopes, and estimate E(B-V) under the assumption of a constant intrinsic UV slope for LAEs. These quantities are used to estimate dust-corrected star formation rates (SFRs). Comparison between the observed Ly{alpha} luminosity and that predicted by the dust-corrected SFR yields the Ly{alpha} escape fraction. We also measure the Ly{alpha} luminosity function and luminosity density ({rho}_Ly{alpha}_) at 2<z<4. Using this and other measurements from the literature at 0.3<z<7.7 we trace the redshift evolution of {rho}_Ly{alpha}_. We compare it to the expectations from the star formation history of the universe and characterize the evolution of the Ly{alpha} escape fraction of galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/218/10
- Title:
- HET Massive Galaxy Survey (HETMGS)
- Short Name:
- J/ApJS/218/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted an optical long-slit spectroscopic survey of 1022 galaxies using the 10m Hobby-Eberly Telescope (HET) at McDonald Observatory. The main goal of the HET Massive Galaxy Survey (HETMGS) is to find nearby galaxies that are suitable for black hole mass measurements. In order to measure accurately the black hole mass, one should kinematically resolve the region where the black hole dominates the gravitational potential. For most galaxies, this region is much less than an arcsecond. Thus, black hole masses are best measured in nearby galaxies with telescopes that obtain high spatial resolution. The HETMGS focuses on those galaxies predicted to have the largest sphere-of-influence, based on published stellar velocity dispersions or the galaxy fundamental plane. To ensure coverage over galaxy types, the survey targets those galaxies across a face-on projection of the fundamental plane. We present the sample selection and resulting data products from the long-slit observations, including central stellar kinematics and emission line ratios. The full data set, including spectra and resolved kinematics, is available online. Additionally, we show that the current crop of black hole masses are highly biased toward dense galaxies and that especially large disks and low dispersion galaxies are under-represented. This survey provides the necessary groundwork for future systematic black hole mass measurement campaigns.
1006. HH 529 spectroscopy
- ID:
- ivo://CDS.VizieR/J/ApJ/644/1006
- Title:
- HH 529 spectroscopy
- Short Name:
- J/ApJ/644/1006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectra of Herbig-Haro objects are usually characteristic of ionization and excitation in shock-heated gas, whether an internal shock in an unsteady outflow or a bow shock interface with the interstellar medium. We examine the easternmost shock the leading optically visible shock of a Herbig-Haro outflow (HH 529) seen projected on the face of the Orion Nebula, using deep optical echelle spectroscopy, showing that the spectrum of this gas is consistent with photoionization by theta^1^ Ori C. By modeling the emission lines, we determine a gas-phase abundance of Fe that is consistent with the depleted (relative to solar) abundance found in the Orion nebula-evidence for the presence of dust in the nebula and therefore in the Herbig-Haro outflow. The spectrum also allows for the calculation of temperature fluctuations, t^2^, in the nebula and the shock. These fluctuations have been used to explain discrepancies between abundances obtained from recombination lines versus those obtained from collisionally excited lines, although to date there has not been a robust theory for how such large fluctuations (t^2^>0.02) can be.
- ID:
- ivo://CDS.VizieR/J/ApJS/182/378
- Title:
- HI and OVI absorbers in nearby Universe
- Short Name:
- J/ApJS/182/378
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze intergalactic HI and OVI absorbers with {nu}<5000km/s in Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer spectra of 76 active galactic nuclei. The baryons traced by HI/OVI absorption are clearly associated with the extended surroundings of galaxies; for impact parameters <400kpc they are 2-4 times more numerous as those inside the galaxies. This large reservoir of matter likely plays a major role in galaxy evolution. We tabulate the fraction of absorbers having a galaxy of a given luminosity within a given impact parameter ({rho}) and velocity difference ({Delta}v), as well as the fraction of galaxies with an absorber closer than a given {rho} and {Delta}v. We identify possible "void absorbers" ({rho}>3Mpc to the nearest L_*_ galaxy), although at v<2500km/s all absorbers are within 1.5Mpc of an L>0.1L_*_ galaxy. The absorber properties depend on {rho}, but the relations are not simple correlations.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/471
- Title:
- HI data of galaxies from Kazarian's lists
- Short Name:
- J/A+AS/126/471
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 21-cm neutral hydrogen line has been measured for the first time in 39 non-Seyfert type galaxies from Kazarian list, with the Nancay radiotelescope. The line profiles, widths at 20% and 50% of the peak intensity, radial velocities as well as total fluxes are presented. The values of radial velocity are in fairly good agreement with those obtained from optical spectra. The width values at 20% of the peak vary in wide range from 113km/s (KAZ 579) to 608km/s for KAZ 566. Nine of our objects remained undetected, whether their HI-flux was too faint, the integration time too short, or the frequency sighted wrong. However, for part of them, there were positive hint of detection. Comments on individual objects are given.
- ID:
- ivo://CDS.VizieR/J/MNRAS/429/2143
- Title:
- Hidden population of AM CVns in the SDSS
- Short Name:
- J/MNRAS/429/2143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the latest results from a spectroscopic survey designed to uncover the hidden population of AM Canum Venaticorum (AM CVn) binaries in the photometric database of the Sloan Digital Sky Survey (SDSS). We selected ~2000 candidates based on their photometric colours, a relatively small sample which is expected to contain the majority of all AM CVn binaries in the SDSS (expected to be ~50). We present two new candidate AM CVn binaries discovered using this strategy: SDSS J104325.08+563258.1 and SDSS J173047.59+554518.5. We also present spectra of 29 new cataclysmic variables, 23 DQ white dwarfs and 21 DZ white dwarfs discovered in this survey. The survey is now approximately 70 per cent complete, and the discovery of seven new AM CVn binaries indicates a lower space density than previously predicted. From the essentially complete g~19 sample, we derive an observed space density of (5+/-3)*10^-7^pc^-3^; this is lower than previous estimates by a factor of 3. The sample has been cross-matched with the GALEX All-Sky Imaging Survey database, and with Data Release 9 of the UKIRT (United Kingdom Infrared Telescope) Infrared Deep Sky Survey (UKIDSS). The addition of UV photometry allows new colour cuts to be applied, reducing the size of our sample to ~1100 objects. Optimising our followup should allow us to uncover the remaining AM CVn binaries present in the SDSS, providing the larger homogeneous sample required to more reliably estimate their space density.
- ID:
- ivo://CDS.VizieR/J/A+A/651/A9
- Title:
- HIFI molecular line survey of SgrB2 (M)
- Short Name:
- J/A+A/651/A9
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present a full analysis of a broadband spectral line survey of Sagittarius B2 (Main), one of the most chemically rich regions in the Galaxy located within the giant molecular cloud complex Sgr B2 in the Central Molecular Zone. Our goal is to derive the molecular abundances and temperatures of the high-mass star-forming region Sgr B2(M) and thus its physical and astrochemical conditions. Sgr B2(M) was observed using the Heterodyne Instrument for the Far-Infrared (HIFI) on board the Herschel Space Observatory in a spectral line survey from 480 to 1907GHz at a spectral resolution of 1.1MHz, which provides one of the largest spectral coverages ever obtained toward this high-mass star-forming region in the submillimeter with high spectral resolution and includes frequencies >1THz that are unobservable from the ground. We modeled the molecular emission from the submillimeter to the far-infrared using the XCLASS program, which assumes local thermodynamic equilibrium (LTE). For each molecule, a quantitative description was determined taking all emission and absorption features of that species across the entire spectral range into account. Because of the wide frequency coverage, our models are constrained by transitions over an unprecedented range in excitation energy. Additionally, we derived velocity resolved ortho/para ratios for those molecules for which ortho and para resolved molecular parameters are available. Finally, the temperature and velocity distributions are analyzed and the derived abundances are compared with those obtained for Sgr B2(N) from a similar HIFI survey. A total of 92 isotopologues were identified, arising from 49 different molecules, ranging from free ions to complex organic compounds and originating from a variety of environments from the cold envelope to hot and dense gas within the cores. Sulfur dioxide, methanol, and water are the dominant contributors. Vibrationally excited HCN (v2=1) and HNC (v2=1) are detected as well. For the ortho/para ratios, we find deviations from the high temperature values between 37 and 180%. In total 14% of all lines remain unidentified. Compared to Sgr B2(N), we found less complex molecules such as CH_3_OCH_3_, CH_3_NH_2_, or NH_2_CHO, but more simple molecules such as CN, CCH, SO, and SO_2_. However some sulfur bearing molecules such as H_2_CS, CS, NS, and OCS are more abundant in N than in M. The derived molecular abundances can be used for comparison to other sources and for providing further constraints for astrochemical models.
