A Robotic Wide‐Angle Hα Survey of the Southern Sky

Gaustad, John E.; McCullough, P. R.; Rosing, W.; Buren, D. van

doi:10.1086/323969

Cited by 434 publications

(483 citation statements)

References 35 publications

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“…It is almost certainly responsible for the anomalously high DM of PSR J0537−69 ( Table 13). As seen in radio continuum (Hughes et al 2007) and Hα (Gaustad et al 2001), 30 Doradus is not far from the nominal center of the LMC at (a 30D , ) d 30D =(05 h 40 m , - 69 ¢ 00 ) and it is believed to be at a similar distance. We model its electron density as a spherical Gaussian distribution:…”

Section: The Magellanic Cloudsmentioning

confidence: 91%

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

Yao¹,

Manchester²,

Wang³

2017

ApJ

1,052

997

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We present a new model for the distribution of free electrons in the Galaxy, the Magellanic Clouds, and the intergalactic medium (IGM) that can be used to estimate distances to real or simulated pulsars and fast radio bursts (FRBs) based on their dispersion measure (DM). The Galactic model has an extended thick disk representing the so-called warm interstellar medium, a thin disk representing the Galactic molecular ring, spiral arms based on a recent fit to Galactic H II regions, a Galactic Center disk, and seven local features including the Gum Nebula, Galactic Loop I, and the Local Bubble. An offset of the Sun from the Galactic plane and a warp of the outer Galactic disk are included in the model. Parameters of the Galactic model are determined by fitting to 189 pulsars with independently determined distances and DMs. Simple models are used for the Magellanic Clouds and the IGM. Galactic model distances are within the uncertainty range for 86 of the 189 independently determined distances and within 20% of the nearest limit for a further 38 pulsars. We estimate that 95% of predicted Galactic pulsar distances will have a relative error of less than a factor of 0.9. The predictions of YMW16 are compared to those of the TC93 and NE2001 models showing that YMW16 performs significantly better on all measures. Timescales for pulse broadening due to interstellar scattering are estimated for (real or simulated) Galactic and Magellanic Cloud pulsars and FRBs.

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Section: The Magellanic Cloudsmentioning

confidence: 91%

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

Yao¹,

Manchester²,

Wang³

2017

ApJ

1,052

997

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“…We also examined the spectral energy distributions (SEDs) and the correlation between measured radio fluxes and Balmer line fluxes estimated from the SuperCOSMOS H-alpha Survey (SHS; Gaustad et al 2001) Hα images (the MASH part of the sample) or found in the literature (the previously known fraction of the sample). We also present derived distances, radii and physical properties of the detected objects.…”

Section: Introductionmentioning

confidence: 99%

A pilot study of the radio‐continuum emission from MASH planetary nebulae

et al. 2011

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Key words astronomical data bases: miscellaneous -planetary nebulae: general -radiation mechanisms: thermal -radio continuum: ISM We report an Australia Telescope Compact Array (ATCA) radio-continuum observations of 26 planetary nebulae (PNe) at wavelengths of 3 and 6 cm. This sample of 26 PNe were taken from the Macquarie/AAO/Strasbourg Hα PNe (MASH) catalogue and previous lists. We investigate radio detection quality including measured and derived parameters for all detected or marginally detected PNe from this combined sample. Some 11 objects from the observed sample have been successfully detected and parametrized. Except for one, all detected PNe have very low radio surface brightnesses. We use a statistical distance scale method to calculate distances and ionised masses of the detected objects. Nebulae from this sample are found to be large (>0.2 pc in diameter) and highly diluted which indicates old age. For 21 PNe from this sample we list integrated Hα fluxes and interstellar extinction coefficients, either taken from the literature or derived here from the Balmer decrement and radio to Hα ratio methods. Finally, our detected fraction of the MASH pilot sample is relatively low compared to the non-MASH sub-sample. We conclude that future radio surveys of the MASH sample must involve deeper observations with better uv coverage in order to increase the fraction of detected objects and improve the quality of the derived parameters.

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“…Furthermore, VB could only use the Hipparcos input catalogue (HIC) to determine the proper-motion direction of the central star. As the Hipparcos catalogue is now completed, its astrometrical data together with the almost complete Hα allsky surveys Virginia Tech Spectral Survey 1 (VTSS; Dennison et al 1997) and Southern Hemispheric Hα Sky Survey Atlas 1 (SHASSA; Gaustad et al 2001), the VB sample is reanalysed here, now using the Hα emission line.…”

Section: Introductionmentioning

confidence: 99%

To see or not to see a bow shock

Brown¹,

Bomans²

2005

A&A

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Abstract. OB-stars have the highest luminosities and strongest stellar winds of all stars, which enables them to interact strongly with their surrounding ISM, thus creating bow shocks. These offer us an ideal opportunity to learn more about the ISM. They were first detected and analysed around runaway OB-stars using the IRAS allsky survey by van Buren et al. (1995, AJ, 110, 2614. Using the geometry of such bow shocks information concerning the ISM density and its fluctuations can be gained from such infrared observations. As to help to improve the bow shock models, additional observations at other wavelengths, e.g. Hα, are most welcome. However due to their low velocity these bow shocks have a size of ∼1 • , and could only be observed as a whole with great difficulties. In the light of the new Hα allsky surveys (SHASSA/VTSS) this is no problem any more. We developed different methods to detect bow shocks, e.g. the improved determination of their symmetry axis with radial distance profiles. Using two Hα-allsky surveys (SHASSA/VTSS), we searched for bow shocks and compared the different methods. From our sample we conclude, that the correlation between the direction of both proper motion and the symmetry axis determined with radial distance profile is the most promising detection method. We found eight bow shocks around HD 17505, HD 24430, HD 48099, HD 57061, HD 92206, HD 135240, HD 149757, and HD 158186 from 37 candidates taken from van Buren et al. (1995, AJ, 110, 2614. Additionally to the traditional determination of ISM parameters using the standoff distance of the bow shock, another approach was chosen, using the thickness of the bowshock layer. Both methods lead to the same results, yielding densities (∼1 cm −3 ) and the maximal temperatures (∼10 4 K), that fit well to the up-to-date picture of the Warm Ionised Medium.

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A Robotic Wide‐Angle Hα Survey of the Southern Sky

Cited by 434 publications

References 35 publications

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

A New Electron-Density Model for Estimation of Pulsar and FRB Distances

A pilot study of the radio‐continuum emission from MASH planetary nebulae

To see or not to see a bow shock

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