Palomar Gattini-IR: Survey Overview, Data Processing System, On-sky Performance and First Results
Palomar Gattini-IR: Survey Overview, Data Processing System, On-sky Performance and First Results
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DOI：
10.1088/1538-3873/ab6069
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发表时间：
2019-10
影响因子：
3.5
通讯作者：
K. De;M. Hankins;M. Kasliwal;A. Moore;E. Ofek;S. Adams;M. Ashley;A. Babul;A. Bagdasaryan
中科院分区：
文献类型：
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作者：
K. De;M. Hankins;M. Kasliwal;A. Moore;E. Ofek;S. Adams;M. Ashley;A. Babul;A. Bagdasaryan
Palomar Gattini-IR是在Palomar天文台运行的一种新的广域、近红外(NIR)机器人时间域测量。使用安装了氢气探测器的30厘米望远镜，Gattini-IR实现了25平方英尺的视场(FOV)。度。像素比例为8。“，J波段为7。在这里，我们介绍了帕洛玛·加蒂尼-IR的系统设计、测量操作、数据处理系统和空中性能。作为名义调查的一部分，加蒂尼-IR每晚扫描≈7500平方度的天空，到银河系平面外15.7AB的中位数5σ深度。这项调查覆盖了≈15,000平方度的天空，从Palomar可以看到，平均节奏为2天。一个实时数据处理系统从天空拍摄的抖动原始图像中产生堆叠的科学图像，以及点扩展函数拟合源目录和从从观测时间起的中位数延迟≈4小时内从减去中识别出的瞬时候选者。经校准的数据产品达到了≈0的天文测量精度(RMS)。对于信噪比为10的源，相对于Gaia DR2为7，优于≈0。对于亮度高于≈12织女星的源，为35。对于比≈12织女星亮度更高、比≈8.5织女星饱和星等弱的光源，在PSF-Fit光源星表中实现的测光精度(RMS)优于≈3%，这是根据两微米全天巡天星表进行校准的。对于亮度大于5σ极限星等的光源，注入图像的瞬变候选者的探测效率优于90%。对于亮度大于13毫克的光源，注入光源的光度恢复精度为3%，天体测量恢复均方根为≈0。“9.通过叠加多次实地考察生成的参考图像，在60%的天空中实现了≳16.5AB MAG的深度，而在银河系平面上受到混淆的限制。利用比任何其他现有近红外成像仪大40倍的视场≈，加蒂尼-IR正在探测局部宇宙中最红和最尘埃的瞬变，例如附近星系中被尘埃遮挡的超新星，银河系内大型灭绝柱后面的新星，银河系平面上变红的微透镜事件，以及凉爽和尘埃遮挡的恒星的变化。我们给出了自试运行开始以来确定的瞬变和变量的结果。
Palomar Gattini-IR is a new wide-field, near-infrared (NIR) robotic time domain survey operating at Palomar Observatory. Using a 30 cm telescope mounted with a H2RG detector, Gattini-IR achieves a field of view (FOV) of 25 sq. deg. with a pixel scale of 8.″7 in J-band. Here, we describe the system design, survey operations, data processing system and on-sky performance of Palomar Gattini-IR. As a part of the nominal survey, Gattini-IR scans ≈7500 square degrees of the sky every night to a median 5σ depth of 15.7 AB mag outside the Galactic plane. The survey covers ≈15,000 square degrees of the sky visible from Palomar with a median cadence of 2 days. A real-time data processing system produces stacked science images from dithered raw images taken on sky, together with point-spread function (PSF)-fit source catalogs and transient candidates identified from subtractions within a median delay of ≈4 hr from the time of observation. The calibrated data products achieve an astrometric accuracy (rms) of ≈0.″7 with respect to Gaia DR2 for sources with signal-to-noise ratio > 10, and better than ≈0.″35 for sources brighter than ≈12 Vega mag. The photometric accuracy (rms) achieved in the PSF-fit source catalogs is better than ≈3% for sources brighter than ≈12 Vega mag and fainter than the saturation magnitude of ≈8.5 Vega mag, as calibrated against the Two Micron All Sky Survey catalog. The detection efficiency of transient candidates injected into the images is better than 90% for sources brighter than the 5σ limiting magnitude. The photometric recovery precision of injected sources is 3% for sources brighter than 13 mag, and the astrometric recovery rms is ≈0.″9. Reference images generated by stacking several field visits achieve depths of ≳16.5 AB mag over 60% of the sky, while it is limited by confusion in the Galactic plane. With a FOV ≈40× larger than any other existing NIR imaging instrument, Gattini-IR is probing the reddest and dustiest transients in the local universe such as dust obscured supernovae in nearby galaxies, novae behind large columns of extinction within the galaxy, reddened microlensing events in the Galactic plane and variability from cool and dust obscured stars. We present results from transients and variables identified since the start of the commissioning period.