- ID:
- ivo://CDS.VizieR/J/ApJS/241/2
- Title:
- Ionization profiles of 8 Galactic H II regions
- Short Name:
- J/ApJS/241/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Green Bank Telescope radio recombination line (RRL) data, we analyze the role of leaking radiation from HII regions in maintaining the ionization of the interstellar medium (ISM). We observed a sample of eight Galactic HII regions of various sizes, morphologies, and luminosities. For each region, the hydrogen RRL intensity decreases roughly as a power-law with the distance from the center of the region. This suggests that radiation leaking from the HII region is responsible for the majority of surrounding ionized gas producing RRL emission. Our results further indicate that the hydrogen RRL intensity appears to be fundamentally related to the HII region sizes traced by their photodissociation regions, such that physically smaller HII regions show a steeper decrease in intensity with an increasing distance from the region centers. As a result, giant HII regions may have a much larger effect in maintaining the ionization of the ISM. For six of the eight observed HII regions, we find a decrease in the ^4^He^+^/H^+^ abundance ratio with an increasing distance, indicating that He-ionizing photons are being absorbed within the ionization front of the HII region. There is enhanced carbon RRL emission toward directions with strong continuum background, suggesting that the carbon emission is amplified by stimulated emission.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/407/2475
- Title:
- Ionized gas in E/S0 galaxies with dust lanes
- Short Name:
- J/MNRAS/407/2475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of multicolour observations of 30 E/S0 galaxies with dust lanes. For each galaxy we obtained broad-band images and narrow-band images using interference filters isolating the H{alpha}+[NII] emission lines to derive the amount and morphology of dust and ionized gas. To improve the wavelength coverage we retrieved data from the Sloan Digital Sky Survey and Two Micron All Sky Survey and combined these with our data. Ionized gas is detected in 25 galaxies and shows in most cases a smooth morphology, although knots and filamentary structure are also observed in some objects.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A131
- Title:
- Ionized Gas Kinematics in MaNGA AGN
- Short Name:
- J/A+A/659/A131
- Date:
- 17 Mar 2022 00:05:59
- Publisher:
- CDS
- Description:
- Feedback from active galactic nuclei (AGN) in general seems to play an important role in the evolution of galaxies, although the impact of AGN winds on their host galaxies is still pending on detailed analysis. We analyse the kinematics of a sample of 170 AGN host galaxies as compared to those of a matched control sample of nonactive galaxies from the MaNGA survey in order to characterise and estimate the extents of the Narrow Line Region (NLR) and of the kinematically disturbed region (KDR) by the AGN. We define the observed NLR radius (r_NLR,o_) as the farthest distance from the nucleus within which both [OIII]/H{beta} and [NII]/H{alpha} ratios fall in the AGN region of the BPT diagram and the H equivalent width is required to be larger than 3.0{AA}. The extent of the KDR (rKDR,o) is defined as the distance from the nucleus within which the AGN hosts galaxies shows a more disturbed gas kinematics than the control galaxies. The AGN [OIII]5007 luminosity ranges from 10^39^ to 10^41^erg/s, and the kinematics derived from the [OIII] line profiles reveal that, on average, the most luminous AGN (L[OIII]>3.8x10^40^erg/s) possess higher residual difference between the gaseous and stellar velocities and velocities dispersion than their control galaxies in all the radial bins. Spatially resolved NLR's and KDR's were found in 55 and 46 AGN host galaxies, with corrected radii 0.2<r_KDR,c_<2.3kpc and 0.4<r_NLR,c_<10.1kpc, with a relation between the two given by logr_KDR,c_=(0.53+/-0.12)logr_NLR,c_+(1.07+/-0.22), respectively. On average, the extension of the KDR corresponds to about 30 per cent of that of the NLR. Assuming that the KDR is due to an AGN outflow, we have estimated ionised gas mass outflow rates that range between 10^-5^ and ~1M_{sun}_/yr, and kinetic powers that range from 10^34^ to 10^40^erg/s. Comparing the power of the AGN ionised outflows with the AGN luminosities, they are always below the 0.05 LAGN model threshold for having a an important feedback effect on their respective host galaxies. The mass outflow rates (and power) of our AGN sample correlate with their luminosities, populating the lowest AGN luminosity range of the correlations previously found for more powerful sources.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A67
- Title:
- Ionized gas maps of local U/LIRGs
- Short Name:
- J/A+A/590/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 2D study of star formation at kpc and sub-kpc scales of a sample of local (z<0.1) U/LIRGs, based on near-IR VLT-SINFONI observations. We obtained integrated measurements of the star formation rate (SFR) and star formation rate surface density, together with their 2D distributions, based on Br_gamma and Pa_alpha emission. We observe a tight linear correlation between the SFR derived from our extinction-corrected measurements and that derived from 24 micron data, and a reasonable agreement with SFR derived from total IR luminosity. Our near-IR measurements are on average a factor 3 larger than optical SFR, even when extinction corrections are applied. We found that LIRGs have a median-observed star formation rate surface density of 1.72M_{sun}_/yr/kpc^2^ for the extinction-corrected distribution, whilst ULIRGs have 0.23M_{sun}_/yr/kpc^2, respectively. These median values for ULIRGs increase up to 2.90M_{sun}_/yr/kpc^2^, when only their inner regions, covering the same size as the average FoV of LIRGs, are considered. We identified a total of 95 individual SF clumps in our sample, with sizes within 60-1500pc, and extinction-corrected Pa_alpha luminosities of 10^5^-10^8^L_{sun}_. Star-forming clumps in LIRGs are about ten times larger and thousands of times more luminous than typical clumps in spiral galaxies. Clumps in ULIRGs have sizes similar (x0.5-1) to those of high-z clumps, having Pa_alpha luminosities similar to some high-z clumps, and about 10 times less luminous than the most luminous high-z clumps identified so far. We also observed a change in the slope of the L-r relation. A likely explanation is that most luminous galaxies are interacting and merging, and therefore their size represents a combination of the distribution of the star-forming clumps within each galaxy in the system plus the effect of the projected distance.
7005. Ionized nebulae in M31
- ID:
- ivo://CDS.VizieR/J/A+AS/92/625
- Title:
- Ionized nebulae in M31
- Short Name:
- J/A+AS/92/625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep CCD imagery in H{alpha} and [SII] is presented of the major spiral arms of M31 with particular attention given to the data reduction and the analysis of the [SII]/H{alpha} flux ratios. A diffuse ionized gas noted in the images is analyzed which shows higher [SII]/H{alpha} ratios, and 967 discrete nebulae are listed with gray-scale images, finding charts, and absolute fluxes. The differential H-alpha luminosity function is found to have a slope of -0.95 for brighter objects and flattens out below a critical level. The curve is shown to correspond to the point at which single-star ionization accounts for the H{alpha} luminosities and is consistent with previous observations. The catalog of objects and fluxes is the largest existing sample of this type, and the unresolved objects in the sample are considered to be planetary nebulae.
- ID:
- ivo://CDS.VizieR/J/ApJ/510/104
- Title:
- Ionizing Stars of Extragalactic H II Regions
- Short Name:
- J/ApJ/510/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Medium-resolution spectra from 3650 to 10000 {AA} are presented for 96 giant H II regions distributed in 20 spiral galaxies. In order to interpret the data, we have calculated two separate grids of photoionization models, adopting single-star atmospheres (Kurucz) and star clusters synthesized with different initial mass functions (IMFs) as ionizing sources. Additional models were computed with more recent non-LTE stellar atmospheres, in order to check the effects of different stellar ionizing fluxes. We use the radiation softness parameter {eta}'=([O II]/[O III])/([S II]/[S III]) of Vilchez & Pagel (1988MNRAS.231..257V) to test for a metallicity dependence of the effective temperatures of the ionizing stars. Our results are consistent with a significant decrease in mean stellar temperatures of the ionizing stars with increasing metallicity. The magnitude of the effect, combined with the behavior of the He I {lambda}5876/H{beta} ratio, suggest a smaller upper mass limit for star formation at abundances higher than solar, even when considering the effects of metallicity on stellar evolution and atmospheric line blanketing. However, the exact magnitudes of the stellar temperature and IMF variations are dependent on the choice of stellar atmosphere and evolution models used, as well as on uncertainties in the nebular abundance scale at high metallicities. Our results also constrain the systematic behavior of the ionization parameter and the N/O ratio in extragalactic H II regions. The observed spectral sequences are inconsistent with current stellar evolution models, which predict a luminous, hot W-R stellar population in evolved H II regions older than 2-3 Myr. This suggests either that the hardness of the emitted Lyman continuum spectrum has been overestimated in the models or that some mechanism disrupts the H II regions before the W-R phases become important.
- ID:
- ivo://CDS.VizieR/J/AJ/159/216
- Title:
- Ions density in the CGM of low mass galaxy groups
- Short Name:
- J/AJ/159/216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore how environment affects the metallicity of the circumgalactic medium (CGM) using 13 low-mass galaxy groups (two to five galaxies) at <z_abs_>=0.25 identified near background quasars. Using quasar spectra from the Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) and from Keck/High Resolution Echelle Spectrometer (Keck/HIRES) or the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph (VLT/UVES), we measure column densities of or determine limits on CGM absorption lines. We use a Markov Chain Monte Carlo approach with Cloudy to estimate metallicities of cool (T~104K) CGM gas within groups and compare them to CGM metallicities of 47 isolated galaxies. Both group and isolated CGM metallicities span a wide range (-2<[Si/H]<0), where the mean group (-0.54{pm}0.22) and isolated (-0.77{pm}0.14) CGM metallicities are similar. Group and isolated environments have similar distributions of HI column densities as a function of impact parameter. However, contrary to isolated galaxies, we do not find an anticorrelation between HI column density and the nearest group galaxy impact parameter. We additionally divided the groups by member luminosity ratios (i.e., galaxy-galaxy and galaxy-dwarf groups). While there was no significant difference in their mean metallicities, a modest increase in sample size should allow one to statistically identify a higher CGM metallicity in galaxy-dwarf groups compared to galaxy-galaxy groups. We conclude that either environmental effects have not played an important role in the metallicity of the CGM at this stage and expect that this may only occur when galaxies are strongly interacting or merging or that some isolated galaxies have higher CGM metallicities due to past interactions. Thus, environment does not seem to be the cause of the CGM metallicity bimodality.
- ID:
- ivo://CDS.VizieR/II/321
- Title:
- IPHAS DR2 Source Catalogue
- Short Name:
- II/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The INT/WFC Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS) is a 1860 deg^2^ imaging survey of the Northern Milky Way at red visible wavelengths. It covers Galactic latitudes |b|<5{deg} and longitudes l=30 to 215{deg} in the broad-band r, i and narrow-band H-alpha filters using the Wide Field Camera (WFC) on the 2.5-m Isaac Newton Telescope (INT) in La Palma. IPHAS Data Release 2 (DR2) is the first quality-controlled and globally calibrated source catalogue derived from the survey, providing single-epoch photometry for 219 million unique sources across 92% of the footprint. The observations were carried out between 2003 and 2012 at a median seeing of 1.1 arcsec (sampled at 0.33 arcsec/pixel) and to a mean 5-sigma depth of 21.2 (r), 20.0 (i) and 20.3 (H-alpha). The photometric calibration is in the Vega magnitude system and carries an external precision of 0.03mag (root-mean-square error). The catalogue includes all the sources which have been detected at a signal-to-noise ratio of 5 or better in at least one band. Many applications will require a combination of quality criteria to be applied to avoid faint stars or confused sources. The choice of quality criteria tensions completeness against reliability, and hence depends on the requirements of a project. To aid users, the data release paper (arXiv:1406.4862) recommends two sets of quality criteria, named "a10" and "a10point", which should satisfy most projects. As a minimum, the "a10" criteria select objects which have been detected at the minimum level of 10-sigma in all bands, without being saturated. Additional constraints are provided by the "a10point" criteria, which require objects to be point sources free of blending, unaffected by nearby bright stars, as well as being unsaturated >10-sigma detections in all bands. Sources in both categories are flagged in the catalogue using the boolean columns a10 and a10point. Imaging and auxiliary data are available from the project website (www.iphas.org).
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/3388
- Title:
- IPHAS new extended planetary nebulae release 1
- Short Name:
- J/MNRAS/443/3388
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of our search for new, extended planetary nebulae (PNe) based on careful, systematic, visual scrutiny of the imaging data from the Isaac Newton Telescope Photometric Halpha Survey of the Northern Galactic plane (IPHAS). The newly uncovered PNe will help to improve the census of this important population of Galactic objects that serve as key windows into the late-stage evolution of low- to intermediate-mass stars. They will also facilitate study of the faint end of the ensemble Galactic PN luminosity function. The sensitivity and coverage of IPHAS allows PNe to be found in regions of greater extinction in the Galactic plane and/or those PNe in a more advanced evolutionary state and at larger distances compared to the general Galactic PN population. Using a set of newly revised optical diagnostic diagrams in combination with access to a powerful, new, multiwavelength imaging data base, we have identified 159 true, likely and possible PNe for this first catalogue release. The ability of IPHAS to unveil PNe at low Galactic latitudes and towards the Galactic Anticentre, compared to previous surveys, makes this survey an ideal tool to contribute to the improvement of our knowledge of the whole Galactic PN population.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A140
- Title:
- IPHAS-selected classical Be stars
- Short Name:
- J/A+A/591/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a semi-automatic procedure to obtain fundamental physical parameters and distances of classical Be (CBe) stars, based on the Barbier-Chalonge-Divan (BCD) spectrophotometric system. Our aim is to apply this procedure to a large sample of CBe stars detected by the IPHAS photometric survey, to determine their fundamental physical parameters and to explore their suitability as galactic structure tracers. In this paper we describe the methodology used and the validation of the procedure by comparing our results with those obtained from different independent astrophysical techniques for subsamples of stars in common with other studies. We also present a test case study of the galactic structure in the direction of the Perseus Galactic Arm, in order to compare our results with others recently obtained with different techniques and the same sample of stars. We did not find any significant clustering of stars at the expected positions of the Perseus and Outer Galactic Arms, in agreement with previous studies in the same area that we used for verification.