共查询到20条相似文献，搜索用时 15 毫秒
1.
1 IntroductionTheblazarsPKS 1 62 2 2 97,3C 454 .3andCTA 1 0 2werefirstlydetectedasγ raysourcesby Fig .1 TheCOMPTELspectraoftheflareandquiescentstate (top)aswellasthecombinedCOMPTEL/EGRETspectrumoftheflarestateforPKS 1 62 2 -2 97(bottom) .EGRET/CGRO [1 ,2 ,3 ] .WehaveconsistentlyanalyzedtheCOMPTELdata (0 .75-3 0MeV)onthese 3blazars.Inouranalysesweselected 2 8CGROviewingperiods (VPs)forPKS 1 62 2 2 97between’91and’97,and 2 2VPsfor 3C 454 .3andCTA 1 0 2between… 相似文献
2.
Yoichi Takeda Gang Zhao Masahide Takada-Hidai Yu-Qin Chen Yu-ji Saito Hua-Wei Zhang 《中国天文和天体物理学报》2003,3(4):316-340
We performed an extensive non-LTE analysis of the neutral sodiumlines of Na I 5683/5688, 5890/5896, 6154/6161, and 8183/8195 in disk/halo starsof types F-K covering a wide metallicity range (-4 [Fe/H] +0.4), using ourown data as well as data collected from the literature. For comparatively metal-rich disk stars (-1 [Fe/H] +0.4) where the weaker 6154/6161 lines are thebest abundance indicators, we confirmed [Na/Fe] ～ 0 with an "upturn" (i.e., ashallow/broad dip around -0.5 [Fe/H] 0) as already reported in previousstudies. For the metal-deficient halo stars, where the much stronger 5890/5896 or8183/8195 lines subject to considerable (negative) non-LTE corrections amountingto 0.5 dex have to be used, our analysis suggests mildly "subsolar" [Na/Fe] valuesdown to ～ -0.4 (with a somewhat large scatter of ～±0.2 dex) on the average at thetypical halo metallicity of [Fe/H] ～ -2, followed by a rise again to a near-solar ratioof [Na/Fe] ～ 0 at the very metal-poor regime [Fe/H] ～ -3 to -4. These resultsare discussed in comparison with the previous observational studies along with thetheoretical predictions from the available chemical evolution models. 相似文献
3.
We performed an extensive non-LTE analysis of the neutral sodium lines of Na I 5683/5688, 5890/5896, 6154/6161, and 8183/8195 in disk/halo stars of types F-K covering a wide metallicity range (-4 (?) [Fe/H] (?) +0.4), using our own data as well as data collected from the literature. For comparatively metal-rich disk stars (-1(?) [Fe/H] (?) +0.4) where the weaker 6154/6161 lines are the best abundance indicators, we confirmed [Na/Fe]- 0 with an "upturn" (i.e., a shallow/broad dip around -0.5 (?) [Fe/H](?) 0) as already reported in previous studies. For the metal-deficient halo stars, where the much stronger 5890/5896 or 8183/8195 lines subject to considerable (negative) non-LTE corrections amounting to 0.5 dex have to be used, our analysis suggests mildly "subsolar" [Na/Fe] values down to--0.4 (with a somewhat large scatter of-±0.2 dex) on the average at the typical halo metallicity of [Fe/H] --2, followed by a rise again to a near-solar ratio of [Na/Fe] - 0 at the very metal-poor regime [Fe/H]--3 to -4 相似文献
4.
5.
理论部分,10.织女星和牛郎星,解:(a)假设这两颗星的位置坐标分别为:织女星(α1,δ1)=(279.23538°,38.78547°);牛郎星(α2,δ2)=(297.69875°,8.87036°)。根据球面几何余弦定律:cos[a]=cos[b]cos[c]+sin[b]sin[c]cos[A]。三角形中,b=(90-δ1),c=(90-δ2)且A=(α2-α1)。 相似文献
6.
《时间频率公报》2002,(1)
侧阅比年1月日 开始S刀J汀(UT)极大结束级别加映X END】翻[P(UT)(UT) 任恤 廿州间娜(间一O。5一0.8一3.7一5.1一3一0一5。6一1 .0一1.3~2。2一3。O姗姗雌哪姗优幻,伪刃1肠,1O知1仪抖3一0.9一4。3一1。4一O。,一1。6一1 .2~7。4一4。5一0.7一2。6 任认汾认 V工FLF娜(户)从(dB) -一1。4 一一4.1,+1.5 一一2.5,+2.5 一一4.1 -一6.3 -一2.3 一一6.3,+3.2 一一6.8,+6.6 一一0.5 一一2.1一+++一+,二,自月二,‘.且口且月J内‘,二心二姗姗侧﹄哪姗﹄姗哪哪7 2 77一吕02八U‘.‘0一一一一一84‘0 72‘且‘且0‘.1月t一︸︸一︸9,l心曰0弓口… 相似文献
7.
赵刚 《中国天文和天体物理学报》1993,(4)
本文确定了贫金属矮星和亚巨星的重元素丰度.基于高分辨率高信噪比光谱得到27颗样本星的锶、钇、锆、钡、镧、铈和铕丰度.主要结果为:(1)第一峰区元素锶-钇-锆显示了奇偶效应,在晕族星中钇相对于锶和锆过贫。(2)对[Fe/H]>-2.5的恒星钇丰度为常数([Y/Fe]=-0.06).(3)对于[Fe/H]<-1.7的样本星,随金属丰度减小钡过贫增加·(4)镧和铈相对于铁过贫.(5)在金属丰度-1.0>[Fe/H]>- 2.0 区间,铕表现过富.(6)对[Y/Fe],[Zr/Fe]和[Ba/Fe]存在约0.1dex的本质弥散. 相似文献
8.
利用 12年的Lageos 1卫星激光测距资料 (1990 - 2 0 0 1)解算得到了地球定向参数 (EOP) ,将该序列的结果与同期的EOP(IERS)C0 4进行比较 ,其外符精度为 :极移XP— 0 .4 0mas,YP— 0 .4 2mas ,日长变化Dr— 0 .0 35ms。 相似文献
9.
广义相对论中静态荷电球体的一组内解 总被引：1，自引：0，他引：1
李鉴增 《中国天文和天体物理学报》1983,(3)
本文在假定物质密度ρ_m=μr~α,电荷密度 ρ_e=ρ_0r~βe~(-λ/2)的情况下,严格求解 Einstein-Maxwell 场方程,得出了静态荷电球体的一组内解,把文[4]、[6]的结果作为自己的特例包括在内。 相似文献
10.
《时间频率公报》2000,(1)
开始SD叼又r(仃r) 0922 0411 0以8 0戈场 01的 优犯5 0抖2 0339 0415 0124极大结束级别MAX ENDI侧[P(I了I,)(Ur)0936 11加D3 以加04501一的01价4310532 05441一0120 02172一 SPA 1尹匆(间鲡(娜)一3 .7一16.2E一0 .4一0.6一1 .0一2.0一0 .4一0.6一2 .5一3.8 班叭 叨万仰(脾) 班认 1万△A(dB) 12.0一4 .4一3 .1 1 .3 2 .8似3303500415创270142优巧51一0339DI以叨Dl05202一03(犯D3 一0 .3一1 .5一1 .6一4 .0一10.1 0 一0 .8 一1 .9 一0 .9, 0.5一10.1, 17.6飞︸,几2 97 ;…0‘l‘12︸6一一一一一一0 .9, 1,024 11.一8 .3, 6.8 0 .… 相似文献
11.
《天文和天体物理学研究(英文版)》2021,(9)
We present here the results of broadband spectral analysis of a low-mass X-ray binary and a black hole candidate 4 U 1957+1 1.The source was observed nine times with the Nuclear Spectroscopic Telescope A rray(NuSTAR) between September 2018 and November 2019.During these observations,the spectral state of 4 U 1957+11 evolved marginally.The disc dominant spectra are described well with a hot,multicolor disc blackbody with disc temperature varying in the range kT_(in)～1.35-1.86 keV and a non-thermal component having a steep slope(Γ=2-3).A broad Fe emission line feature(5-8 keV) was observed in the spectra of all the observations.The relativistic disc model was used to study the effect of distance,inclination and the black hole mass on its spin.Simulations indicate a higher spin for smaller distances and lower black hole masses.At smaller distances and higher masses,spin is maximum and almost independent of the distance.An inverse correlation exists between the spin and the spectral hardening factor for all the cases.The system prefers a moderate spin of about 0.85 for black hole masses between 4-6 M_⊙ for a 7 kpc distance. 相似文献
12.
《时间频率公报》2002,(5)
20(理年 开始SrARr(Ur) 的45 似39 0310 0218 0423极大州叭X(Ul、)0751优巧5031802530520价0605300321结束END(UT)08100310D0抖004020635级别1州[P111一21 SPA任伙班认 廿Vl万L卫仰(间鲡(间畅(间△A(dB)一0 .9一1.3一0一1.7一1.6一一1.2一0 .6一0.6一0一4.3一4.1一一1.4,+0.7一1 .4一1.4一+2.4朋日27 28 28 2929一1 .2一5 .6一2 .4一1 .6一5.8一2.3 0一1 .5,+3.4 十2 .2 ++‘工,山IL低频甚低频传播突然扰动(续1)~~… 相似文献
14.
《时间频率公报》2002,(1)
溉幻2年1月日 开始S以滚r(UT)任恢廿州”)仓和(户) 斗姚任认 叨JLF娜(”)从(dB) -一4。O -一1., ~一5.8 一一,.0,十1.7 -一4.8 -一0 .7 一一6.2,+1.1 一一5.0 -一3 .1 -一1 .07尸0 4 240 .1门1 004一一一一一72‘12口」 ..…八U,几..几产O月」 一一︸︸︸优匕50317加55俐乃优岛5给束级别END协企(UT)优拼9卜O洲010110UI伙刃53+03102心曰4几U叹甘心口0 7 2.几n甘一︸︸一︸47心J八U心曰n甘心J .工L,人n﹄一︸︸一︸︸.且飞甘‘.二..几一1 .7一0 .5·2.2一0 .6一3 .5+0 .4︸十一口.人..山‘.‘闷甘﹃洲︸nU OU,盛,产O口丙J月了Q︼… 相似文献
15.
Zhao D. F. 《天文研究与技术》1999,(Z1)
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ48Ｌｉｂ (ＨＤ1 42 983,ＨＲ5 941 ,Ｒ .Ａ .( 2 0 0 0 ) :1 5 :5 8:0 9;Ｄｅｃ ( 2 0 0 0 ) :- 1 4:1 6 :43;ｓｐｅｃｔｒａｌｔｙｐｅ :Ｂ/Ｉａｂｅ ,Ｖｍａｇ:4 88Ｂ Ｖｃｏｌｏｒ:- 0 1 0 ) ,ｉｓｏｎｅｏｆｗｅｌｌ ｋｎｏｗＶ/Ｒｖａｒｉａｂｌｅｓｈｅｌｌｓｔａｒｓ.Ｉｔｉｓａｌｏｎｇｔｅｒｍｃｙｃｌｅｖａｒｉａｂｌｅｓｔａｒｗｉｔｈｖａｒｉａｂｌｅｌｉｎｅｐｒｏｆｉｌｅｓ.ＩｔｓｅｍｉｓｓｉｏｎｌｉｎｅｓａｌｓｏｓｈｏｗｔｈａｔｔｈｅｒａｄｉａｌｖｅｌｏｃｉｔｙａｎｄＶ/Ｒｒａｔｉ… 相似文献
16.
In this work,we perform a statistical investigation towards 50 high-mass clumps using data from the Bolocam Galactic Plane Survey(BGPS)and Millimetre Astronomy Legacy Team 90-GHz survey(MALT90).Eleven dense molecular lines(N_2H~+(1–0),HNC(1–0),HCO~+(1–0),HCN(1–0),HN~(13)C(1–0),H~(13)CO~+(1–0),C_2H(1–0),HC_3N(10–9),SiO(2–1),~(13)CS(2–1)and HNCO(4_(4,0)-3_(0,3)))are detected.N_2H~+ and HNC are shown to be good tracers for clumps in various evolutionary stages since they are detected in all the fields.The detection rates of N-bearing molecules decrease as the clumps evolve,but those of O-bearing species increase with evolution.Furthermore,the abundance ratios[N_2H~+]/[HCO~+]and log([HC_3N]/[HCO~+])decline with log([HCO~+])as two linear functions,respectively.This suggests that N~+2H~+ and HC_3N transform to HCOas the clumps evolve.We also find that C_2H is the most abundant molecule with an order of magnitude 10~(-8).In addition,three new infall candidates,G010.214–00.324,G011.121–00.128 and G012.215–00.118(a),are discovered to have large-scale infall motions and infall rates with an order of magnitude 10~(-3)M_⊙yr~(-1). 相似文献
17.
《时间频率公报》2007,(6)
UTC(NTSC)-GPS TIME2007年6月PRN01PRN02PRN03PRN04PRN05PRN06日MJD ns UT ns UT ns UT ns UT ns UT ns UT1542523(0938)2(0142)7(1130)1(1914)4(0610)-7(1026)2542530(0934)1(0138)13(1126)1(1910)0(0606)-1(1022)354254-4(0930)7(0134)17(1122)0(1906)-5(0602)-4(1018)4542554(0926)3(0130)5(1118)0(1902)--5(1014)5542560(0922)-3(1114)--3(0554)-654257-4(0918)-1(0122)--1(1854)-5(0550)-9(1006)7542580(0914)0(0118)10(1106)1(1850)-4(0546)-8(1002)8542594(0910)3(0114)6(1102)0(1846)-2(0542)-9542607(0906)3(01… 相似文献
18.
《时间频率公报》2000,(3)
20(刃年3月日级别1倒[P任叭1万 SnA WjF匆(脚)班认LF仰(脾)匆,(脾)△A(dB)00户b一吕4 ..…1几,且,且,且,孟一一一一一O声8,1尸bZ ..…nUn甘,上11‘.几一一一一一一一心1月l,1 .1‘.几 开始印阴卫T(Ul、) 0叭0 0517 0650 0洲5 以43极大州叭X(Ur)0347051906540355以50结束END(UT)0420U05550725例350501D.j‘勺叹口,矛7.050101330301023503150508020203()70别1032205400310054503050415一一5.6, 18.4O产户02司14nU RU‘.几,几2一一一一一8,翻0 0 Jll07月i,12一一一一一子0 4Q沙0心」0 .Oq︼2月呼一一一一一‘0 7 4 4C,︸ ..…04月… 相似文献
19.
《时间频率公报》1999,(4)
1999年 4月 日 开始START(UT) 0557 0519 0747 0840 0338极大MAX(L汀)06 130525075408530348结束END(UT)06500555081309450435级别IMP SPA LF 铆(娜)骊(娜)一1 .2一1,6一1 .6一1 .8一0 .6一1 .1一2 .1一4 .5一1 .4一1 .5一1 .0一1,0一2 .3一2 .6一4 .4一4 .7一0 .3一0 .3一0 .7一0 .7 SPA SFA VLFLF仰(娜)队(dB) 一一3.6 一一5.9 一一2.0 一一5.0,十2.9 一一6.0刁.人1工1且,七弓几 一3 .1 一4 .4一8 .8, 9.3 一1 .1 一1 .4一十一一,二,且,‘,人11030600230501032002470320003905160326025604000105u063704000325035304000500… 相似文献
20.
《时间频率公报》2004,(1)
20(抖年 1月 日 开始 别胜RT (Ur) 细困组 1侧[P 任恢 LF 仰(间娜(间 SPA班认 Vl万1万 △和(件)△A(dB) 0119 0劣犯 肠31 优巧5 以刃5 仪润4 0210 0617 0346 0508 01幻 03泌 仅抖9 0311 阅努 0105 0努5 肠加 0410 0522 一2.2 一2。6 一4 .6 一1 .3 一5.8 一2.7 一3.6 一8 .1 一1 .7 一10.0 一2 .0 一4 .9 +15.1 一2 .6 一10.9,+5,7 ﹃且月.且 ‘.一2 一4 .9 一10.6 一10.1 一9 .7 一4 .7 +3 .0 +2 .4 一4 .4,+7.2 1 .3,+3.9 +5 .2 2内J 21几月」 内J 00尹07久」 一一一一一 +一++++十 ‘工2内J‘.几月J 23内庵︸32 咤︸咤︺ J67 伙56… 相似文献