The IPHAS catalogue of Hα emission-line sources in the northern Galactic plane

Abstract

We present a catalogue of point‐source Hα emission‐line objects selected from the INT/WFC Photometric Hα Survey (IPHAS) of the northern Galactic plane. The catalogue covers the magnitude range 13 ≤r′≤ 19.5 and includes Northern hemisphere sources in the Galactic latitude range −5° < b < 5°. It is derived from ∼1500 deg2 worth of imaging data, which represents 80 per cent of the final IPHAS survey area. The electronic version of the catalogue will be updated once the full survey data become available. In total, the present catalogue contains 4853 point sources that exhibit strong photometric evidence for Hα emission. We have so far analysed spectra for ∼300 of these sources, confirming more than 95 per cent of them as genuine emission‐line stars. A wide range of stellar populations are represented in the catalogue, including early‐type emission‐line stars, active late‐type stars, interacting binaries, young stellar objects and compact nebulae. The spatial distribution of catalogue objects shows overdensities near sites of recent or current star formation, as well as possible evidence for the warp of the Galactic plane. Photometrically, the incidence of Hα emission is bimodally distributed in (r′−i′). The blue peak is made up mostly of early‐type emission‐line stars, whereas the red peak may signal an increasing contribution from other objects, such as young/active low‐mass stars. We have cross‐matched our Hα‐excess catalogue against the emission‐line star catalogue of Kohoutek & Wehmeyer, as well as against sources in SIMBAD. We find that fewer than 10 per cent of our sources can be matched to known objects of any type. Thus IPHAS is uncovering an order of magnitude more faint (r′ > 13) emission‐line objects than were previously known in the Milky Way.

IPHAS and the symbiotic stars

“…Section 3 is a discussion of the spectroscopically confirmed new symbiotic systems, while Sect. 4 outlines the majority group of mimics revealed in our spectra: among A&A 509, A41 (2010) Witham et al (2008). these there are several notable, rare object types. Discussion and perspectives are presented in Sect.…”

“…The possible symbiotic stars in Paper I were selected from the list of IPHAS Hα emitters by Witham et al (2008), which in turn was built when the survey's photometric catalogue was only partially completed. We now need to produce a complete, magnitude limited sample of candidates, scanning the whole IPHAS photometric catalogue in a similar way as done by Viironen et al (2009b) for compact PNe.…”

“…Combination of these properties with constraints from 2MASS near-IR data defines the selection criteria adopted in Paper I. There, a list of about one thousand symbiotic star candidates was drawn up from the set of IPHAS Hα emitters available at that time (Witham et al 2008). As shown in Paper I, this list suffers from significant contamination by reddened Be stars and young stellar objects, which are frequent in the Galactic plane.…”

TheXMM-Newtonserendipitous survey

“…A1, page 10 of 22 iv) the MaxBCG galaxy clusters catalogue from SDSS (Koester et al 2007); v) the 2XMMi/SDSS DR7 cross-correlation (Pineau et al 2011); vi) the 3rd release of the RAVE catalogue (Siebert et al 2011); vii) the IPHAS Hα emission line source catalogue (Witham et al 2008); viii) the WISE All-Sky data Release (Cutri & et al 2012); ix) the AKARI mid-IR all-sky survey (Ishihara et al 2010) and version 1.0 of the all-sky survey bright source catalogue (Yamamura et al 2010); x) the Spitzer IRAC survey of the galactic center (Ramírez et al 2008); xi) the GLIMPSE Source Catalogue (I + II + 3D Churchwell et al 2009); xii) the IRAC-24 micron optical source catalogue (Surace et al 2004); and xiii) the Planck Early Release Compact Source Catalogue (Planck Collaboration VII 2011). Table 4 lists, for a selection of archival catalogues, the number of EPIC detections having at least one catalogue entry in the 99.73% (3 Gaussian σ) confidence region.…”

Candidate planetary nebulae in the IPHAS photometric catalogue

“…IRASCat: The IRAS catalogue (PSC/SSC/SSS) from which the IRAS data of the object was taken. f12, f25, f60, f100: IRAS fluxes at 12, 25, 60 and 100 μm (Corradi et al 2008), S = IPHAS extended nebulae catalogue (S09), M = PN in MASH or MASH-II catalogues Miszalski et al 2008), W = IPHAS emitter catalogue (Witham et al 2008). class: Preliminary classification based on follow-up spectroscopy.…”