Grantecan spectroscopic observations and confirmations of Planetary Nebulae candidates in the Northern Galactic Plane

TL;DR

This study uses the GTC telescope to spectroscopically confirm 55 faint planetary nebula candidates from IPHAS, discovering 5 new PNe and demonstrating the survey's effectiveness in identifying PNe in obscured, distant, and evolved regions of the Galaxy.

Contribution

The paper presents the first large-scale spectroscopic confirmation of faint PNe candidates from IPHAS, including new discoveries and detailed plasma diagnostics, enhancing the Galactic PNe catalog.

Findings

Confirmed 46 'True' PNe and identified 5 new PNe.

Achieved an 89% success rate in candidate confirmation.

Provided comprehensive plasma properties and kinematic data for new PNe.

Abstract

We present Grantecan 10 m telescope (GTC) spectroscopic confirmations of 55 faint Planetary Nebulae (PNe) candidates discovered largely in the INT Photometric H$_\alpha$ Survey of the Northern Galactic Plane (IPHAS) by our pro-am collaboration. We confirm 46 of them as 'True' (T), 4 as 'Likely' (L) and 5 as 'Possible' (P) PNe and including 5 new PNe central star (CSPN) discoveries. This was from observations of 62 new candidates yielding a maximum PN discovery success rate of 89%. The sensitivity and longer wavelength coverage of IPHAS allows PNe to be found in regions of greater extinction and at these lower Galactic latitudes, including PNe in a more advanced evolutionary state and at larger distances compared to previously known Galactic PNe. We use an holistic set of observed characteristics and optical emission-line diagnostics to confirm candidates. Plasma properties have been determined in a self-consistent way using PyNeb. This work is facilitated by the functionality of our powerful, multi-wavelength database 'HASH' (Hong Kong, Australian Astronomical Observatory, Strasbourg Observatory H-alpha Planetary Nebula catalogue) that federates known imaging, spectroscopy and other pertinent data for all Galactic T, L, P PNe and the significant numbers of mimics. Reddenings, corrected radial velocities and PNe electron density and temperature estimates are provided for these new PNe where possible.