The Pan-STARRS 1 Photometric Reference Ladder, Release 12.0 (1303.3634v1)

Abstract: As of 2012 Jan 21, the Pan-STARRS 1 3\pi Survey has observed the 3/4 of the sky visible from Hawaii with a minimum of 2 and mean of 7.6 observations in 5 filters, g_p1, r_p1, i_p1, z_p1, y_p1. Now at the end of the second year of the mission, we are in a position to make an initial public release of a portion of this unprecedented dataset. This article describes the PS1 Photometric Ladder, Release 12.01 This is the first of a series of data releases to be generated as the survey coverage increases and the data analysis improves. The Photometric Ladder has rungs every hour in RA and at 4 intervals in declination. We will release updates with increased area coverage (more rungs) from the latest dataset until the PS1 survey and the final re-reduction are completed. The currently released catalog presents photometry of \approx 1000 objects per square degree in the rungs of the ladder. Saturation occurs at g_p1, r_p1, i_p1 \approx 13.5; z_p1 \approx 13.0; and y_p1 \approx 12.0. Photometry is provided for stars down to g_p1, r_p1, i_p1 \approx 19.1 in the AB system. This data release depends on the rigid `Ubercal' photometric calibration using only the photometric nights, with systematic uncertainties of (8.0, 7.0, 9.0, 10.7, 12.4) millimags in (g_p1, r_p1, i_p1, z_p1, y_p1). Areas covered only with lower quality nights are also included, and have been tied to the Ubercal solution via relative photometry; photometric accuracy of the non-photometric regions is lower and should be used with caution.

• The paper introduces a comprehensive photometric catalog using the Ubercal method to achieve systematic uncertainties as low as 8.0–12.4 millimags.
• It details observations from the PS1 3π Survey, covering approximately 1000 objects per square degree across five filters for precise calibration.
• The work provides a robust framework for future surveys by advancing calibration techniques for both ground- and space-based astronomical observations.

An Analysis of the Pan-STARRS 1 Photometric Reference Ladder, Release 12.01

The paper discusses the Pan-STARRS 1 Photometric Ladder, Release 12.01, which is part of the data collected by the Pan-STARRS 1 (PS1) $3\pi$ Survey. This survey aims to cover three-quarters of the sky visible from Hawaii, with a focus on creating a photometric reference catalog of unprecedented scale and accuracy. The ultimate objective of this initiative is to enhance precision in photometric calibration for astronomical observations and ultimately provide a reference standard indispensable to both ground-based and space-based telescopes.

Key Observations and Methodology

As of the date reflected in the paper, the Pan-STARRS 1 $3\pi$ Survey had collected data over a significant portion of the sky, aiming for multiple observations across five different filters. The data are organized into a Photometric Ladder, a structured release strategy designed to update and expand concurrently with improvements in data processing and increased sky coverage.

At this release stage, the catalog includes photometric data for approximately 1000 objects per square degree, with photometric measurements extending from relatively bright magnitudes down to significant depths in astronomical terms. The data calibration depends heavily on the "Ubercal" photometric calibration method, which anchors measurements to the most photometric nights to minimize systematic uncertainties. The paper reports systematic uncertainties as low as 8.0 to 12.4 millimags across the various filters.

Implications and Innovations

The Pan-STARRS project illustrates a significant advancement in the ability to perform high-precision photometry over a vast area of the sky. By combining a large field of view with advanced data processing pipelines, Pan-STARRS provides crucial data for a variety of scientific analyses, including the characterization of transient astronomical events, galaxy clustering observations, and solar system dynamics.

Furthermore, the Ubercal method of calibration represents a robust approach that mitigates traditional challenges in photometric accuracy due to atmospheric variations and instrumental discrepancies. The residual systematic uncertainties reported are indicative of potential improvements achievable as data analysis techniques become more sophisticated, and as further data are collected in the ongoing survey.

Future Prospects

The full realization of the PS1 $3\pi$ Survey goal of complete and precise coverage will lead to a comprehensive network of calibrated photometric references across the observed sky. As such, it will serve as an essential resource for astronomers requiring precise calibration of their observational data across multiple telescopic and observational platforms.

In the broader scope, this endeavor has laid the groundwork for upcoming large-scale surveys and telescope installations, including the LSST, which aims to further extend these high-precision techniques to even wider areas of the sky. Lessons learned from the Pan-STARRS implementation will be crucial in guiding future projects in both their organizational strategies and methodological frameworks.

Conclusion

This release of the Pan-STARRS 1 Photometric Reference Ladder exemplifies an extraordinary step forward in astronomical photometry. By providing a dense and precise catalog of photometric data, this work empowers astronomers to achieve new levels of accuracy in their measurement techniques. This initiative will continue to evolve, driven by ongoing improvements in both survey coverage and data processing, solidifying its crucial role in the astronomical research community.