本文關(guān)鍵詞：M51星系盤上HCN J=1-0發(fā)射線的成圖觀測(cè)　出處：《中國(guó)科學(xué):物理學(xué) 力學(xué) 天文學(xué)》2014年09期 　論文類型：期刊論文

  更多相關(guān)文章： 星系-星際介質(zhì) 星系-NGC 星際介質(zhì)-分子氣體

【摘要】：為了解致密分子氣體在星系盤上的分布,我們使用IRAM 30 m望遠(yuǎn)鏡對(duì)M51的HCN J=1-0分子發(fā)射線進(jìn)行了成圖觀測(cè)(角分辨率為28").成圖區(qū)域達(dá)4'×5'(1'~2.9 kpc),是目前為止對(duì)M51 HCN J=1-0發(fā)射線進(jìn)行的最為延展的一次成圖觀測(cè).將之與NRO 45 m望遠(yuǎn)鏡觀測(cè)得到的CO J=1-0發(fā)射線數(shù)據(jù)進(jìn)行比較,我們對(duì)M51星系內(nèi)致密分子氣體與總分子氣體分布的差異與相關(guān)性等特性進(jìn)行了討論.HCN分布呈現(xiàn)出向星系中心集中的趨勢(shì),中心區(qū)域的HCN積分強(qiáng)度是星系盤上的3 4倍.在HCN積分強(qiáng)度圖中也觀測(cè)到了由CO發(fā)射所示蹤的氣體旋臂.M51總HCN光度是中心主波束區(qū)域(kpc尺度)的5倍,這說(shuō)明了依然存在很多的致密分子氣體分布在星系中心核區(qū)之外.在距星系光學(xué)中心42''內(nèi)的區(qū)域(包含核球區(qū)的星系內(nèi)盤),距離星系中心越遠(yuǎn),HCN/CO的積分強(qiáng)度比越小;而在遠(yuǎn)離星系中心的星系盤上(大于42")該比值基本保持恒定.對(duì)于星系盤上的大部分區(qū)域,IHCN和ICO具有非常緊密的線性相關(guān)性,最小二乘法擬合的斜率為1.2.而對(duì)于核球區(qū)它們的擬合斜率則要高得多(2.3).所有這些都說(shuō)明了致密分子氣體的性質(zhì)(例如含量、發(fā)射條件、HCN的豐度)在核球區(qū)和星系盤上是不一樣的.
[Abstract]:In order to understand the distribution of dense molecular gas on galactic disk. Using the IRAM 30m telescope, we have mapped the emission lines of M51's HCN JJ _ (1-0) molecule (angular resolution is 28 "). The mapping area is 4'脳 5 ~ (-1). (2. 9 kpcs). Is by far the most extended mapping observation of the M51 HCN JJ 1-0 emission line. Co obtained from the NRO 45 m telescope. JN1-0 emission line data were compared. We discuss the difference and correlation between the distribution of dense molecular gas and total molecular gas in M51 galaxy. HCN distribution tends to be concentrated towards the center of the galaxy. The HCN integral intensity in the central region is 3 on the disk. In the HCN integral intensity diagram, the total HCN luminosity of the gas rotation arm. M51, which is traced by CO emission, is also observed to be the central main beam region (. Kpc scale). This indicates that there are still a lot of dense molecular gases distributed outside the central nucleus of the galaxy, and the region within 42 'from the optical center of the galaxy (the inner disk of the galaxy containing the sphere of nucleus) is further away from the center of the galaxy. The smaller the integral intensity ratio of HCN/CO is; On the disk far away from the center of the galaxy (> 42 "), the ratio is basically constant. There is a very close linear correlation between IHCN and ICO for most of the region of the disk. The slope fitted by the least square method is 1.2, and the slope is much higher for the nuclear sphere. All these indicate the properties of the dense molecular gas (such as content, emission condition). HCN abundance) is different in the nuclear sphere from the galactic disk.
【作者單位】： 中國(guó)科學(xué)院紫金山天文臺(tái);中國(guó)科學(xué)院大學(xué);中國(guó)科學(xué)院射電天文重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家自然科學(xué)基金資助項(xiàng)目(批準(zhǔn)號(hào):11173059)
【分類號(hào)】：P152
【正文快照】： 大量的觀測(cè)研究表明,恒星形成于巨型分子云中(其主要成分是氫分子),并且恒星形成活動(dòng)非常依賴于局域密度,這就是類星體紅移發(fā)現(xiàn)者提出的Schmidt恒星形成定律[1].在巨型分子云中,CO分子的豐度僅次于氫分子,其轉(zhuǎn)動(dòng)躍遷(尤其是J=1-0躍遷)在平均密度大于約300 cm?3的區(qū)域就很容易

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