SUMMARY OF PROPOSAL 71193

DR. TADAYUKI TAKAHASHI
TAKAHASI@astro.isas.jaxa.jp

ISAS
3-1-1 YOSHINODAI
SAGAMIHARA
KANAGAWA JAPAN 229-8510
Tel: 0427-59-8150 Fax: 0427-59-8455
Medium: 4GBDAT
Subject: COSMIC X-RAY BACKGROUND DEEP SURVEYS AND OTHER

ASCA OBSERVATION OF FAINT HARD X-RAY SOURCES


ABSTRACT

The origin of the Cosmic X-ray background (CXB) has been one of the key issues of X-ray astronomy. We propose follow up observations of 8 selected hard X-ray sources discovered by the serendipitous source survey project with ASCA. AXAF observations of these sources to determine positions were already approved. These sources have 2-10 keV fluxes below 5 x 10**(-13) erg/cm2/s. ASCA 0.7-2/2-10 keV counting rates that require them to either have power law photon indecies flatter than 1.0, or if they have intrinsic slopes of 1.7, have column density greater than Nh = 2 x 10**22/cm2.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
TADAYUKI TAKAHASHIISASJAPAN
YOSHIHIRO UEDAISASJAPAN
YOSHITAKA ISHISAKITOKYO METRO U.JAPAN
KOUJI OHTAKYOTO U.JAPAN
MASAYUKI AKIYAMAKYOTO U.JAPAN
TORU YAMADATOHOKU U.JAPAN

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)AXJ1025+4714
A
156.4921 47.2397
50 ks
N
Y
P
0.00500
1
2)AXJ0431-0526
A
67.9287 -5.4405
70 ks
N
Y
P
0.00300
1
3)AXJ1510+0742
A
227.5975 7.7006
70 ks
N
Y
P
0.00300
1
4)AXJ1951+5609
A
297.7650 56.1658
90 ks
N
Y
P
0.00200
1