arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 2008.00834astro-ph.GAastro-ph.SR
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银河系灭绝定律:II。一个新的星际吸收带在7700光年处,比任何已知的DIB都要宽。

Galactic extinction laws: II. Hidden in plain sight, a new interstellar absorption band at 7700 Å broader than any known DIB

J. Maíz Apellániz, R. H. Barbá, J. A. Caballero, R. C. Bohlin, C. Fariña

摘要:

我们已经探测到一个宽的星际吸收带,中心接近7700 nm,半高宽为176.6 $\pm$ 3.9 nm。这是在光学范围内探测到的第一个这样的吸收带,并且比众多的弥漫星际带(DIB)要宽得多。直到现在它还未被发现,因为它部分隐藏在O $_2$产生的A大地带后面。这个波段是用STIS@HST光谱发现的,后来又用进一步的STIS和地面光谱在大量不同类型的恒星(OB星、BA超巨星、红巨星)样本中发现。测量了该带的EW,并与我们对同一样品的消光和KI $λλ$ 7667.021,7701.093测量值进行了比较。该载体在弥漫和半透明的银河ISM中无处不在,但在OB星周围的环境中耗尽。特别是,在富含分子碳的视线中,它似乎不存在或几乎不存在。这种行为类似于$σ$型DIB,它起源于低/中密度紫外线暴露的ISM,但在高密度紫外线屏蔽的分子云中耗尽。我们还提出了一个更新我们以前的工作之间的关系$E(4405-5495)$和$R_{5495}$,并将我们的结果到ISM的一般模型。

英文摘要:

We have detected a broad interstellar absorption band centred close to 7700 Å and with a FWHM of 176.6$\pm$3.9 Å. This is the first such absorption band detected in the optical range and is significantly wider than the numerous diffuse interstellar bands (DIBs). It remained undiscovered until now because it is partially hidden behind the A telluric band produced by O$_2$. The band was discovered using STIS@HST spectra and later detected in a large sample of stars of diverse type (OB stars, BA supergiants, red giants) using further STIS and ground-based spectroscopy. The EW of the band is measured and compared with our extinction and K I $λλ$7667.021,7701.093 measurements for the same sample. The carrier is ubiquitous in the diffuse and translucent Galactic ISM but is depleted in the environment around OB stars. In particular, it appears to be absent or nearly so in sightlines rich in molecular carbon. This behaviour is similar to that of the $σ$-type DIBs, which originate in the low/intermediate-density UV-exposed ISM but are depleted in the high-density UV-shielded molecular clouds. We also present an update on our previous work on the relationship between $E(4405-5495)$ and $R_{5495}$ and incorporate our results into a general model of the ISM.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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