天文学报
天文學報
천문학보
ACTA ASTRONOMICA SINICA
2010年
1期
18-26
,共9页
星系:赛弗特%方法:数值
星繫:賽弗特%方法:數值
성계:새불특%방법:수치
galaxies:Seyfert%methods:numerical
星系中心黑洞质量和核球恒星速度弥散度的紧密关系揭示出准确测量恒星速度弥散度对测定星系中心黑洞质量尤为重要.文中提供了一种利用 SDSS(Sloan Digital Sky Survey)光谱测定速度弥散度及其不确定性的方法.通过对像素空间包含显著特征吸收线的 4 个不同谱区的拟合,得到准确测量恒星速度弥散度σ的光谱区域.文中 4 个拟合波段主要包含的吸收线为 Ca Ⅱ K,Mg Ⅰ b 三重线(波长5 167.5,5 172.7,5 183.6(A))和 CaT(Ca Ⅱ三重线,波长8 498.0,8 542.1,8 662.1(A)).不同区域结果表明,Mg Ⅰ b区由于受到铁族发射线影响,拟合的σ值偏低;Ca Ⅱ K 线区谱线强度很弱,易受限于最小二乘法搜索算法; CaT+Ca Ⅱ K 联合区得出的速度弥散度和只计算 CaT 区域的结果相当.利用该方法,测试了一个红移小于 0.05 的赛弗特星系样本,发现 CaT 区是测速度弥散度的最佳谱区.
星繫中心黑洞質量和覈毬恆星速度瀰散度的緊密關繫揭示齣準確測量恆星速度瀰散度對測定星繫中心黑洞質量尤為重要.文中提供瞭一種利用 SDSS(Sloan Digital Sky Survey)光譜測定速度瀰散度及其不確定性的方法.通過對像素空間包含顯著特徵吸收線的 4 箇不同譜區的擬閤,得到準確測量恆星速度瀰散度σ的光譜區域.文中 4 箇擬閤波段主要包含的吸收線為 Ca Ⅱ K,Mg Ⅰ b 三重線(波長5 167.5,5 172.7,5 183.6(A))和 CaT(Ca Ⅱ三重線,波長8 498.0,8 542.1,8 662.1(A)).不同區域結果錶明,Mg Ⅰ b區由于受到鐵族髮射線影響,擬閤的σ值偏低;Ca Ⅱ K 線區譜線彊度很弱,易受限于最小二乘法搜索算法; CaT+Ca Ⅱ K 聯閤區得齣的速度瀰散度和隻計算 CaT 區域的結果相噹.利用該方法,測試瞭一箇紅移小于 0.05 的賽弗特星繫樣本,髮現 CaT 區是測速度瀰散度的最佳譜區.
성계중심흑동질량화핵구항성속도미산도적긴밀관계게시출준학측량항성속도미산도대측정성계중심흑동질량우위중요.문중제공료일충이용 SDSS(Sloan Digital Sky Survey)광보측정속도미산도급기불학정성적방법.통과대상소공간포함현저특정흡수선적 4 개불동보구적의합,득도준학측량항성속도미산도σ적광보구역.문중 4 개의합파단주요포함적흡수선위 Ca Ⅱ K,Mg Ⅰ b 삼중선(파장5 167.5,5 172.7,5 183.6(A))화 CaT(Ca Ⅱ삼중선,파장8 498.0,8 542.1,8 662.1(A)).불동구역결과표명,Mg Ⅰ b구유우수도철족발사선영향,의합적σ치편저;Ca Ⅱ K 선구보선강도흔약,역수한우최소이승법수색산법; CaT+Ca Ⅱ K 연합구득출적속도미산도화지계산 CaT 구역적결과상당.이용해방법,측시료일개홍이소우 0.05 적새불특성계양본,발현 CaT 구시측속도미산도적최가보구.
The tight relation between the black hole mass and the stellar velocity dis-persion indicates that the velocity dispersion is an important parameter to estimate the black hole mass.A new method is proposed in this paper to measure the stellar velocity dispersion and its uncertainty for a sample of Seyfert galaxies from Sloan Digital Sky Survey(SDSS).Through fitting four spectral regions which contain stellar absorption features in pixel domain including the Ca Ⅱ K,Mg Ⅰ b triplet and Ca Ⅱ triplet absorption lines,we determine a better spectral region to measure the stellar velocity dispersion.The results show a significant difference:the values obtained in Mg Ⅰ b region are smaller due to the contamination from the broad Fe Ⅱ emission lines;the velocity dispersion is easily biased by the searching algorithm in Ca Ⅱ K region because of the weakness of lines;and similar results are derived in Ca Ⅱ K+Ca Ⅱ triplet and Ca Ⅱ K regions.For the Seyfert galaxies with z < 0.05,we conclude that Ca Ⅱ triplet is the best choice to measure the stellar velocity dispersion.
