@misc{06494b7019c844d79a56148f024a64c7,
title = "INTEGRAL Observations of MAXI J1836-194",
abstract = "MAXI J1836-194 (ATEL \#3611) was in the INTEGRAL/IBIS FOV on September 13th from UT 09:15 till 12:56, during the Galactic Bulge monitoring observations (See http://integral.esac.esa.int/BULGE ). It was detected at about 55 mCrab and 50 mCrab (in 18-40 keV) in revolutions 1088 and 1090, respectively. Unfortunately it was not within the JEM-X field of view in any of the pointings for this observation. In the framework of the {"}inner disk >0{"} observations, further pointings were performed by INTEGRAL during revolution 1090. Here, we report on preliminary results of these IBIS and JEM-X observations collected on 2011-09-18 since 03:11:34.0 until 14:48:56.0. MAXI 1836-194 was detected by IBIS/ISGRI at a significance level of 32 sigma and 19 sigma in the 20-40 keV and 40-80 keV bands, respectively (\textasciitilde{}23 ks effective exposure time). The corresponding fluxes are roughly 48 mCrab and 44 mCrab, respectively. The source was also clearly detected by JEM-X at 23 sigma level in the 3-10 keV energy band with a flux of about 38 mCrab (\textasciitilde{}5 ks effective exposure time). The simultaneous IBIS/ISGRI+JEM-X 4-300 keV spectrum can be well described (chi2\_red/d.o.f=1.0/18) by a power-law model with photon index 2.19+/-0.05. There is no evidence of any high-energy cutoff below 200 keV. No disk black-body component (ATEL \#3628) is requested by the JEM-X data. The estimated 3-20 keV and 20-100 keV mean fluxes are 1.0E-9 erg/cm2/s and 6.2E-10 erg/cm2/s, respectively. RXTE/PCA spectra (power-law slope as 1.7-1.8) on August 31 (ATEL \#3618) and September 2 (ATEL \#3628) suggested that MAXI J1836-194 was in the hard/intermediate state at that time. Our INTEGRAL spectral fit and the prominent hard X-ray emission observed suggest MAXI J1836-194 being still in an intermediate state, possibly soft/intermediate as reported in the ATEL \#3626. Our findings are consistent with the nature of black-hole candidate proposed for this source, definitely strengthened by the last radio (ATEL \#3628) and optical (ATEL \#3640) observations. Follow-up observations at multi-wavelengths are strongly encouraged. Further INTEGRAL observations are planned. We acknowledge support from the Galactic Bulge group.",
keywords = "Transient, Binary, Black Hole",
author = "\{Del Santo\}, M. and E. Kuulkers and J. Rodriguez and C. Baldovin and E. Bozzo and I. Caballero and \{Cadolle Bel\}, M. and F. Capitanio and J. Chenevez and I. Kreykenbohm and M. Kuehnel and C. Sanchez-Fernandez and K. watanabe and G. Weidenspointer",
year = "2011",
month = sep,
day = "19",
language = "English",
series = "The Astronomer's telegram",
publisher = "R. Rutledge",
number = "ATel \#3652",
type = "Other",
}