Discovery of an Exceptional Optical Nebulosity in the Suspected Galactic SN Iax Remnant Pa 30 Linked to the Historical Guest Star of 1181 CE
The Astrophysical Journal Letters
A newly recognized young Galactic supernova (SN) remnant, Pa 30 (G123.1+4.6), centered on a hot c... more A newly recognized young Galactic supernova (SN) remnant, Pa 30 (G123.1+4.6), centered on a hot central star with a ∼16,000 km s−1 wind velocity, has recently been proposed to be the result of a double-degenerate merger leading to an SN Iax event associated with the guest star of 1181 CE. Here we present deep optical [S ii] λλ6716,6731 images of Pa 30 that reveal an extraordinary and highly structured nebula 170″ in diameter with dozens of long (5″–20″), radially aligned filaments with a convergence point near the hot central star. Optical spectra of filaments indicate a peak expansion velocity ≃1100 km s−1 with electron densities of ≤100–700 cm−3 and a thick shell-like structure resembling its appearance in 22 μm WISE images. No Hα emission was seen ([S ii] λ6716/Hα >5), with the only other line emission detected being faint [Ar iii] λ7136, suggesting a S- and Ar-rich but H-poor remnant. The nebula’s angular size, estimated 2.3 kpc distance, and 1100 km s−1 expansion velocity ar...
A newly recognized young Galactic SN remnant, Pa 30 (G123.1+4.6), centered on a hot central star ... more A newly recognized young Galactic SN remnant, Pa 30 (G123.1+4.6), centered on a hot central star with a ∼16,000 km s −1 wind velocity has recently been proposed to be the result of a double-degenerate merger leading to a SN Iax event associated with the guest star of 1181 CE. Here we present deep optical [S II] λλ6716,6731 images of Pa 30 which reveal an extraordinary and highly structured nebula 170 in diameter with dozens of long (5 − 20) radially aligned filaments with a convergence point near the hot central star. Optical spectra of filaments indicate a peak expansion velocity 1100 km s −1 with electron densities of ≤100 to 700 cm −3 , and a thick shell-like structure resembling its appearance in 22 µm WISE images. No Hα emission was seen ([S II] λ6716/Hα > 5), with the only other line emission detected being faint [Ar III] λ7136 suggesting a S, Ar-rich but H-poor remnant. The nebula's angular size, estimated 2.3 kpc distance, and 1100 km s −1 expansion velocity are consistent with an explosion date around 1181 CE. The remnant's unusual appearance may be due to the photoionization of wind-driven ejecta due to clump-wind interactions caused by the central star's high-luminosity wind.
We present the key results from an intensive and coordinated ten-year amateur observational progr... more We present the key results from an intensive and coordinated ten-year amateur observational programme designed to uncover and confirm Galactic planetary nebulae (PNe). This was undertaken and led by a dedicated group of largely French amateur astronomers in collaboration with professional colleagues. Over this period this group has uncovered a total of 209 spectroscopically confirmed True, Likely, and Possible Galactic PNe, with the work accelerating over the last three years in particular. These new discoveries represent ~5% of all 3831 True, Likely, and Possible Galactic PNe currently known according to the HASH database as of March 2022. A further 610 PNe candidates are awaiting follow-up. These figures demonstrate the power and value of the amateur community in undertaking a coordinated and focused programme such as this.
WISE properties of planetary nebulae from the DSH catalogue
Asymmetrical Planetary Nebulae VI Conference, Apr 1, 2014
VizieR Online Data Catalog: Galactic Open Cluster Candidates (Kronberger+, 2006)
New Planetary Nebulae and Candidates from Multicolour Multiwavelength Surveys
ABSTRACT In the past decade, the Deep Sky Hunters Collaboration has identified more than 200 plan... more ABSTRACT In the past decade, the Deep Sky Hunters Collaboration has identified more than 200 planetary nebula (PN) candidates by scanning the Digitized Sky Survey (DSS) and other publicly available digital resources (SDSS, GALEX, WISE) mostly outside the sky regions covered by the SHS and IPHAS surveys. Amongst these 200 objects, we have identified thus far 106 true, probable and possible PNe, increasing the number of known Galactic PNe in the surveyed fields by about 30%. This contribution presents H-alpha and [OIII] images of 37 new PNe and candidates that have been identified during the past three years with the survey technique mentioned above.
The invariance of DSHs and DVHs under bladder filling changes Mischa S Hoogeman, Stephanie T H Pe... more The invariance of DSHs and DVHs under bladder filling changes Mischa S Hoogeman, Stephanie T H Peeters, Josien de Bois et al. Simulation of ion transport characteristics in a collisionless rf sheath Zu-li Liu, Xing-bin Jing and Kai-lun Yao Experimental investigation on linewidth characteristics of a single-frequency phosphate fiber laser at 1.0 m Can Li, Shanhui Xu, Yu Xiao et al.
WISE propoerties of planetary nebulae from the DSH catalogue
A decade has passed since the discovery of Patchick 1, the first planetary nebula (PN) found by a... more A decade has passed since the discovery of Patchick 1, the first planetary nebula (PN) found by an amateur astronomer since the early days of PN research. Since then, the members of the Deep Sky Hunters (DSH) collaboration have identified ̃200 PN candidates in fields mostly outside of the boundaries covered by the IPHAS and SHS surveys . Further investigations based on narrowband imaging, primarily to reveal H-alpha and [OIII] line emission, and/or spectroscopic observations on 157 of these enabled classifying 64 candidates as true PNe on those morphologies and spectral properties. Additional 42 objects with unavailable spectra are considered as probable or possible PNe based on their morphologies alone. The remaining 51 objects were found to be PN mimics of various nature, such as supernova remnants, interlopers, reflection nebulae, or plate faults. The majority of the PN candidates from the DSH sample were found by the visual inspection of multicolour imagery from the Digitized Sk...
New Milky Way Star Cluster Candidates from DSS and 2MASS
Astrophysics and Space Science Proceedings, 2011
ABSTRACT We present 27 open cluster candidates, including 24 previously unknown, that were found ... more ABSTRACT We present 27 open cluster candidates, including 24 previously unknown, that were found during an ongoing visual inspection of First and Second Generation Digitized Sky Survey (DSS) and Two Micron All Sky Survey (2MASS) images. Employing 2MASS and UKIDSS photometry, 10 of these candidates and three earlier published objects have physical parameters determined by isochrone fitting of their [J,J-H] and [J,J-K] colour-magnitude diagrams (CMDs) and [J-H, J-K] colour-colour diagrams. In order to decontaminate the cluster CMDs from stars belonging to the Milky Way fore- and background, a statistical approach is applied that determines the statistical significance of the density differences between the cluster CMD and the CMD of the Milky Way background. The studied clusters have ages ranging from a few Myr to ≈ 1 Gyr, are only moderately reddened (E(B - V ) ≤ 1. 1) and are situated at distances between 0.95 and 5.5 kpc.
Galactic Open Cluster Candidates (Kronberger+, 2006)
An inspection of DSS and 2MASS images of selected Milky Way regions led to the discovery of 66 st... more An inspection of DSS and 2MASS images of selected Milky Way regions led to the discovery of 66 stellar groupings whose morphologies, color-magnitude diagrams and stellar density distributions suggest that these objects are possible open clusters that are not yet listed in any catalogue. For 24 of these, which we consider to be the most likely candidates, we provide extensive
Proceedings of the International Astronomical Union, 2011
Having surveyed ≈ 10% of the sky, we have identified more than 130 PN candidates by surveying mul... more Having surveyed ≈ 10% of the sky, we have identified more than 130 PN candidates by surveying multicolour Digitized Sky Survey (DSS), Sloan Digitized Sky Survey (SDSS), and combined [O III], Hα and [S II] images. In a first imaging and spectroscopy campaign, 51 objects were identified as true and probable PNe. This work presents an additional 17 probable or possible PNe identified since that study. The majority of these candidates are situated at Galactic latitudes |b| > 5^, with the exception of seven objects located closer to the Galactic plane. Using the techniques described here that do not require any new survey data, we anticipate that many more PNe are waiting to be found, perhaps as many as 90.
A Search for Faint Planetary Nebulae Using the DSS
A group of amateur astronomers (Deep Sky Hunters) has identified ˜50 candidate PNe by visually se... more A group of amateur astronomers (Deep Sky Hunters) has identified ˜50 candidate PNe by visually searching the 1st and 2nd generation red Digital Sky Survey images. Candidate PNe are then observed in Halpha with larger telescopes, primarily the WIYN 3.5-m on Kitt Peak, and the 1.2-m and 1.5-m at Haute-Provence Observatory (OHP). Thus far, ˜20 new PNe have been found. These objects have a strong tendency to have low surface brightness and to be relatively round.
Publications of the Astronomical Society of Australia, 2010
Recent Hα surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary ... more Recent Hα surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary nebula (PN) census. We now know of ∼3000 PNe in the Galaxy, but this is far short of most estimates, typically ~25 000 or more for the total population. The size of the Galactic PN population is required to derive an accurate estimate of the chemical enrichment rates of nitrogen, carbon, and helium. In addition, a high PN count (>20 000) is strong evidence that most main-sequence stars of mass 1–8 M⊙ will go through a PN phase, while a low count (<10 000) argues that special conditions (e.g. close binary interactions) are required to form a PN. We describe a technique for finding hundreds more PNe using the existing data collections of the digital sky surveys, thereby improving the census of Galactic PNe.
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