The second data release of the INT Photometric Hα Survey of the Northern Galactic Plane (IPHAS DR2)
Gentile Fusillo, NP
van Roestel, J
Monthly Notices of the Royal Astronomical Society
Oxford University Press
This is the final version of the article. Available from Oxford University Press via the DOI in this record.
© 2014. The INT/WFC Photometric Hα Survey of the Northern Galactic Plane (IPHAS) is a 1800 deg2 imaging survey covering Galactic latitudes b < 5<sup>°</sup> and longitudes ℓ = 30<sup>°</sup>-215<sup>°</sup> in the r, i, and Hα filters using the Wide Field Camera (WFC) on the 2.5-m Isaac Newton Telescope (INT) in La Palma. We present the first quality-controlled and globally calibrated source catalogue derived from the survey, providing single-epoch photometry for 219 million unique sources across 92 per cent of the footprint. The observations were carried out between 2003 and 2012 at a median seeing of 1.1 arcsec (sampled at 0.33 arcsec pixel-<sup>1</sup>) and to a mean 5σ depth of 21.2 (r), 20.0 (i), and 20.3 (Hα) in the Vega magnitude system. We explain the data reduction and quality control procedures, describe and test the global re-calibration, and detail the construction of the new catalogue.We show that the new calibration is accurate to 0.03 mag (root mean square) and recommend a series of quality criteria to select accurate data from the catalogue. Finally, we demonstrate the ability of the catalogue's unique (r - Hα, r - i) diagram to (i) characterize stellar populations and extinction regimes towards different Galactic sightlines and (ii) select and quantify Hα emission-line objects. IPHAS is the first survey to offer comprehensive CCD photometry of point sources across the Galactic plane at visible wavelengths, providing the much-needed counterpart to recent infrared surveys.
GB, JED, SES, and BTG acknowledge support from the Science and Technology Facilities Council of the United Kingdom (grants: GB and JED – ST/J001333/1, SES – ST/K00106X/1, BTG – ST/I001719/1). HJF and MM-S both acknowledge STFC postgraduate studentships. JED would also like to convey her thanks to the Physics Department of Imperial College London that hosted this project from its inception to 2007 and supported her via a sabbatical year in 2003–04. JF is supported by the Spanish Plan Nacional de I+D+i and FEDER under contract AYA2010-18352. BTG acknowledges funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant agreement no. 320964 (WDTracer). PRG is supported by a Ramón y Cajal fellowship (RYC-2010-05762), and acknowledges support provided by the Spanish MINECO AYA2012–38700 grant. NJW is in receipt of a Fellowship funded by the Royal Astronomical Society of the United Kingdom.
Monthly Notices of the Royal Astronomical Society, 2014, Vol. 444, Issue 4, pp. 3230 - 3257