SPHEREx全天区3.3与3.4微米多环芳香烃发射综合图
A Full-Sky SPHEREx Map of Integrated 3.3 and 3.4 μm PAH Emission
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中文总结 AI 辅助
利用SPHEREx光谱数据生成全天区3.3与3.4-3.5微米PAH发射图，直接追踪小颗粒群体，为研究星际尘埃和异常微波发射提供新工具。
中文摘要 AI 辅助
多环芳香烃（PAHs）在星际介质中普遍存在，是其最小的含碳颗粒之一。它们的红外发射谱带追踪了这种小颗粒群体以及激发它的星际辐射场，并被广泛用于诊断光解离区域、尘埃处理和恒星形成。我们基于SPHEREx QR2 Level-2数据，呈现了3.3微米芳香族C-H伸缩振动和相邻3.4-3.5微米脂肪族复合体的积分辐射度的全天区图。现有的全天区PAH示踪物是宽带的，因此谱带发射只能作为恒星和连续谱发射之上的过量部分来推断；SPHEREx对光谱的采样足够精细，可以直接拟合这些谱带。我们掩蔽了被标记的探测器像素，减去了逐像素的黄道光模型，使用经验导出的点扩散函数减去了点源，并将结果合并为反方差加权的HEALPix图，其分辨率为2.6角分（FWHM），Nside=4096，覆盖探测器4（2.42-3.82微米）的102个窄带通道。在每个天球像素上，我们拟合了连续谱和这两个谱带。合并的谱带辐射度是主要产品；其分解为芳香族和脂肪族组分的结果作为估计值随产品一同发布，并说明了其建模的系统性。这些是首批全天区的PAH谱带发射图，在光谱上分辨了3.3和3.4-3.5微米谱带，也是SPHEREx发布的首批全天区PAH图。由于3.3微米谱带优先由最小的PAHs发射，这些图直接追踪了一个颗粒群体，包括异常微波发射的候选载体，而宽带PAH示踪物只能间接达到这些颗粒。这些图及其相关产品，包括一个可靠性掩膜，均可公开获取，并附有解释性补充材料，网址为https://此URL。
英文摘要
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the interstellar medium and are among its smallest carbonaceous grains. Their infrared emission bands trace this small-grain population together with the interstellar radiation field that excites it, and are widely used to diagnose photodissociation regions, dust processing and star formation. We present full-sky maps of the integrated radiance of the 3.3 $μ$m aromatic C-H stretch and the adjacent 3.4-3.5 $μ$m aliphatic complex, from SPHEREx QR2 Level-2 data. Existing all-sky PAH tracers are broadband, so the band emission can only be inferred as an excess over stellar and continuum emission; SPHEREx samples the spectrum finely enough for the bands to be fitted directly. We mask flagged detector pixels, subtract the per-pixel zodiacal-light model, subtract point sources with an empirically derived PSF, and coadd the results into inverse-variance-weighted HEALPix maps at 2.6' FWHM and Nside=4096 in 102 narrowband channels across Detector 4 (2.42-3.82 $μ$m). At every sky pixel we fit a continuum and the two bands. The combined band radiance is the primary product; its decomposition into the aromatic and aliphatic components is released alongside it as an estimate, with its modelling systematic stated. These are the first full-sky maps of PAH band emission, resolving the 3.3 and 3.4-3.5 $μ$m bands spectrally, and the first full-sky PAH maps from SPHEREx to be released. Because the 3.3 $μ$m band is emitted preferentially by the smallest PAHs, the maps trace directly a grain population, including the candidate carriers of anomalous microwave emission, that broadband PAH proxies reach only indirectly. The maps and their associated products, including a reliability mask, are publicly available with an explanatory supplement at https://research.iac.es/proyecto/radioforegroundsplus/pages/data-products/spherex-pahs.php.
发表机构
- Instituto de Astrofísica de Canarias（加那利天体物理学研究所）
- Universidad de La Laguna (ULL)（拉帕尔马大学）
- The University of Manchester（曼彻斯特大学）
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