scholarly journals Hα fluxes and extinction distances for planetary nebulae in the IPHAS survey of the Northern Galactic Plane

2020 ◽  
Author(s):  
Thavisha E Dharmawardena ◽  
M J Barlow ◽  
J E Drew ◽  
A Seales ◽  
S E Sale ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Galactic Plane ◽  
Planetary Nebulae ◽  
Balmer Line ◽  
Imaging Data ◽  
Mapping Algorithms ◽  
Mapping Algorithm ◽  
Dust Extinction ◽  
Filter Photometry ◽  
Gaia Dr2

Abstract We report Hα filter photometry for 197 northern hemisphere planetary nebulae (PNe) obtained using imaging data from the IPHAS survey. Hα+[N ii] fluxes were measured for 46 confirmed or possible PNe discovered by the IPHAS survey and for 151 previously catalogued PNe that fell within the area of the northern Galactic Plane surveyed by IPHAS. After correcting for [N ii] emission admitted by the IPHAS Hα filter, the resulting Hα fluxes were combined with published radio free-free fluxes and Hβ fluxes, in order to estimate mean optical extinctions to 143 PNe using ratios involving their integrated Balmer line fluxes and their extinction-free radio fluxes. Distances to the PNe were then estimated using three different 3D interstellar dust extinction mapping methods, including the IPHAS-based H-MEAD algorithm of Sale (2014). These methods were used to plot dust extinction versus distance relationships for the lines of sight to the PNe; the intercepts with the derived dust optical extinctions allowed distances to the PNe to be inferred. For 17 of the PNe in our sample reliable Gaia DR2 distances were available and these have been compared with the distances derived using three different extinction mapping algorithms as well as with distances from the nebular radius vs. Hα surface brightness relation of Frew et al. (2016). That relation and the H-MEAD extinction mapping algorithm yielded the closest agreement with the Gaia DR2 distances.

scholarly journals A Gaia DR2 view of the open cluster population in the Milky Way

2018 ◽  
Vol 618 ◽  
pp. A93 ◽  
Author(s):  
T. Cantat-Gaudin ◽  
C. Jordi ◽  
A. Vallenari ◽  
A. Bragaglia ◽  
L. Balaguer-Núñez ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Milky Way ◽  
Galactic Plane ◽  
Galactic Disk ◽  
Open Cluster ◽  
Open Clusters ◽  
Number Of Clusters ◽  
History Of ◽  
Gaia Dr2

Context. Open clusters are convenient probes of the structure and history of the Galactic disk. They are also fundamental to stellar evolution studies. The second Gaia data release contains precise astrometry at the submilliarcsecond level and homogeneous photometry at the mmag level, that can be used to characterise a large number of clusters over the entire sky. Aims. In this study we aim to establish a list of members and derive mean parameters, in particular distances, for as many clusters as possible, making use of Gaia data alone. Methods. We compiled a list of thousands of known or putative clusters from the literature. We then applied an unsupervised membership assignment code, UPMASK, to the Gaia DR2 data contained within the fields of those clusters. Results. We obtained a list of members and cluster parameters for 1229 clusters. As expected, the youngest clusters are seen to be tightly distributed near the Galactic plane and to trace the spiral arms of the Milky Way, while older objects are more uniformly distributed, deviate further from the plane, and tend to be located at larger Galactocentric distances. Thanks to the quality of Gaia DR2 astrometry, the fully homogeneous parameters derived in this study are the most precise to date. Furthermore, we report on the serendipitous discovery of 60 new open clusters in the fields analysed during this study.

scholarly journals The Edinburgh/AAO/Strasbourg Catalogue of Galactic Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 41-41 ◽  
Author(s):  
Q. A. Parker ◽  
M. Hartley ◽  
D. Russeil ◽  
A. Acker ◽  
F. Ochsenbein ◽  
...  
Keyword(s):  
Galactic Plane ◽  
Angular Size ◽  
Planetary Nebulae ◽  
Depth Resolution ◽  
Central Star ◽  
Isolation And Identification ◽  
Large Numbers ◽  
Low Surface Brightness ◽  
Bulge Region ◽  
Version 2.0

We report on version 1.0 of the Edinburgh/AAO/Strasbourg catalogue of new and possible Planetary Nebulae (PN) distributed via cdrom at this meeting. We provide accurate positions, designations, images and other descriptive parameters for the PN. In future releases this will be supplemented by inclusion of spectra and related material such as line ratios, velocities etc.The 900+ PN have been discovered solely from visual scrutiny of narrow-band exposures taken for the AAO/UKST H-alpha survey of the Southern Galactic Plane. Most have classic PN-type morphologies (i.e. bi-polar, rings, shells or ovals). SuperCOSMOS data will soon supersede our visual scanning but it proved an effective preliminary technique to identify candidate PN on the basis of morphology, isolation and identification as an H-alpha nebulosity. We already have confirmatory spectroscopy for ~ 700 objects. Much of our new sample are of very low surface brightness, with no obvious central star, and so have remained undetected in previous surveys. They are revealed here due to the excellent depth, resolution, coverage and uniformity of the H-alpha survey. Many PN are also well extended. The average angular size is 51″ with the median of 27″ but examples extend to several arcminutes. This may indicate many are in a highly evolved state where the central star has faded from easy optical detection and the nebula itself is dissipating into the ambient ISM. Large numbers of candidate PN have also been found in the Galactic Bulge region, most of which have been confirmed via UKST FLAIR/6dF MOS spectroscopy (Parker et al, in preparation and these proceedings).By version 2.0 (release in 2002) we will have doubled the number of Galactic PN accrued from all sources over the last 75 years. This new catalogue should have a profound impact on many aspects of PN research.

scholarly journals Three-dimensional maps of interstellar dust in the Local Arm: using Gaia, 2MASS, and APOGEE-DR14

2018 ◽  
Vol 616 ◽  
pp. A132 ◽  
Author(s):  
R. Lallement ◽  
L. Capitanio ◽  
L. Ruiz-Dern ◽  
C. Danielski ◽  
C. Babusiaux ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Large Scale ◽  
Galactic Plane ◽  
Large Fraction ◽  
Complex Structure ◽  
Dust Emission ◽  
Three Dimensional ◽  
Red Giants ◽  
Photometric Calibration ◽  
The One

Context. Gaia data and stellar surveys open the way to the construction of detailed 3D maps of the Galactic interstellar (IS) dust based on the synthesis of star distances and extinctions. Dust maps are tools of broad use, also for Gaia-related Milky Way studies. Aims. Reliable extinction measurements require very accurate photometric calibrations. We show the first step of an iterative process linking 3D dust maps and photometric calibrations, and improving them simultaneously. Methods. Our previous 3D map of nearby IS dust was used to select low-reddening SDSS/APOGEE-DR14 red giants, and this database served for an empirical effective temperature- and metallicity-dependent photometric calibration in the Gaia G and 2MASS Ks bands. This calibration has been combined with Gaia G-band empirical extinction coefficients recently published, G, J, and Ks photometry and APOGEE atmospheric parameters to derive the extinction of a large fraction of the survey targets. Distances were estimated independently using isochrones and the magnitude-independent extinction KJ−Ks. This new dataset has been merged with the one used for the earlier version of dust map. A new Bayesian inversion of distance-extinction pairs has been performed to produce an updated 3D map. Results. We present several properties of the new map. A comparison with 2D dust emission reveals that all large dust shells seen in emission at middle and high latitudes are closer than 300 pc. The updated distribution constrains the well-debated, X-ray bright North Polar Spur to originate beyond 800 pc. We use the Orion region to illustrate additional details and distant clouds. On the large scale the map reveals a complex structure of the Local Arm. Chains of clouds of 2–3 kpc in length appear in planes tilted by ≃15° with respect to the Galactic plane. A series of cavities oriented along a l ≃ 60–240° axis crosses the Arm. Conclusions. The results illustrate the ongoing synergy between 3D mapping of IS dust and stellar calibrations in the context of Gaia. Dust maps provide prior foregrounds for future calibrations appropriate to different target characteristics or ranges of extinction, allowing us in turn to increase extinction data and produce more detailed and extended maps.

scholarly journals The UV and optical reddening law to the Galactic Bulge and CNO abundances in Bulge planetary nebulae

1993 ◽  
Vol 153 ◽  
pp. 337-338
Author(s):  
N.A. Walton ◽  
M.J. Barlow ◽  
R.E.S. Clegg
Keyword(s):  
Galactic Disk ◽  
Planetary Nebulae ◽  
Line Ratio ◽  
Solar Neighbourhood ◽  
Balmer Line ◽  
Galactic Bulge ◽  
The Mean ◽  
Cno Abundances ◽  
Halo Population ◽  
Selective Extinction

An analysis of the differential ultraviolet extinction towards four bulge planetary nebulae, based on the observed line ratio of He II 1640/4686Å, shows that the ultraviolet reddening law towards the bulge is much steeper than in the solar neighbourhood. An analysis of the optical reddening law for 42 bulge PN, based upon observed Balmer line ratios and Hβ to radio free-free flux ratios, is presented. The optical reddening law towards the bulge is steeper than in the local ISM, and thus the ratio of total to selective extinction, Rv = 2.29 (± 0.50), is lower than the standard solar neighbourhood value of Rv = 3.10.We present abundance determinations, in particular C/H and C/O ratios, for 11 Galactic bulge PN, based on spectrophotometry in the UV from IUE and in the optical from the Anglo-Australian Telescope. The derived abundances are compared with values for PN in the Galactic disk. The mean C/O ratio for bulge PN is significantly lower than that found for Galactic disk PNs. Additionally we present an abundance analysis of the very metal-poor halo population PN M2-29, which is located in the bulge.

scholarly journals Observations of the Diffuse Ultraviolet Background from the UVX Experiment On Space Shuttle

1990 ◽  
Vol 139 ◽  
pp. 227-228
Author(s):  
Richard C. Henry ◽  
Paul D. Feldman ◽  
Jayant Murthy
Keyword(s):  
Interstellar Dust ◽  
Galactic Plane ◽  
Space Shuttle ◽  
Galactic Latitude ◽  
Cosmic Background

The UVX experiment has resulted in confirmation that the diffuse ultraviolet background is low in intensity everywhere and that it is fairly uniform in intensity, both spatially and spectrally. There is no clear evidence that any significant portion of the moderate galactic latitude diffuse cosmic background originates in galactic plane starlight scattering from interstellar dust.

scholarly journals A Rich New Vein of Planetary Nebulae From the AAO/UKST Hα Survey

2003 ◽  
Vol 209 ◽  
pp. 25-32
Author(s):  
Q. A. Parker ◽  
M. Hartley ◽  
D. Russeil ◽  
A. Acker ◽  
D. H. Morgan ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Galactic Plane ◽  
Planetary Nebulae ◽  
Lower Surface ◽  
Large Numbers

We report on an unprecedented source of Planetary Nebulae (PN) discovered from AAO/UKST Hα survey images of the Southern Galactic Plane. A pristine region of PN discovery space is being sampled due to the excellent depth, coverage, resolution and uniformity of the Hα survey. Large numbers of new PN are being found (~1000 so far). They are typically more evolved, obscurred and of lower surface brightness than in most other surveys. The doubling of known PN should have a significant impact on many aspects of PN research.

scholarly journals Expansion parallaxes and intrinsic stellar properties for 15 simple planetary nebulae

2016 ◽  
Vol 12 (S323) ◽  
pp. 354-356 ◽  
Author(s):  
Detlef Schönberner ◽  
Ralf Jacob ◽  
Bruce Balick
Keyword(s):  
Hubble Space Telescope ◽  
Planetary Nebulae ◽  
Line Of Sight ◽  
Radiation Hydrodynamics ◽  
Proper Motions ◽  
Imaging Data ◽  
The Difference ◽  
Stellar Properties ◽  
Angular Expansion ◽  
Shock Fronts

AbstractWe determined individual distances to a small number of rather round, quite regularly shaped planetary nebulae by combining their angular expansion in the plane of the sky with a spectroscopically measured expansion along the line of sight. For this goal, we combined up to three epochs of Hubble Space Telescope imaging data and determined the respective proper motions of rim and shell edges, and of other features as well. Ground-based radial velocities are assigned separately to the nebular rims and shells and used to determine individual distances, thereby assuming that the expansions in the line-of-sight and in the plane of sky are equal. We employed 1D radiation-hydrodynamics simulations of planetary nebulae evolution to correct for the difference between the spectroscopically measured expansion velocities of rim and shell and the expansion speeds of their respective shock fronts.

scholarly journals Distance Determinations from 21 cm Interstellar Absorption-line Measurements

1983 ◽  
Vol 103 ◽  
pp. 541-542 ◽  
Author(s):  
S.R. Pottasch ◽  
R. Gathier ◽  
W.M. Goss
Keyword(s):  
Absorption Line ◽  
Radio Telescope ◽  
Galactic Plane ◽  
Planetary Nebulae ◽  
Interstellar Absorption

HI observations at 21 cm have been made with the Westerbork Synthesis Radio Telescope in the direction of six planetary nebulae located in or near the galactic plane (N 7027, 2440, 6537, 6572, 7026, 7354).

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