We present the results of the analysis of RXTE ( Rossi X-ray Timing Explorer ) observations of the new x-ray transient , SWIFT J1753.5-0127 during its outburst in July , 2005 .
The source was caught at the peak of the burst with a flux of 7.19e-09 ergs-s ^ { -1 } -cm ^ { -2 } in the 3-25 keV energy range and observed until it decreased by about a factor of 10 .
The photon index of the power law component , which is dominant during the entire outburst , decreases from \sim 1.76 to 1.6 .
However , towards the end of the observations the photon index is found to increase , indicating a softening of the spectra .
The presence of an ultrasoft thermal component , during the bright phases of the burst , is clear from the fits to the data .
The temperature associated with this thermal component is 0.4 keV .
We believe that this thermal component could be due to the presence of an accretion disk .
Assuming a distance of 8.5 kpc , L _ { X } / L _ { Edd } \simeq 0.05 at the peak of the burst , for a black hole of mass 10 ~ { } { M } _ { \odot } .
The source is found to be locked in the low/hard state during the entire outburst and likely falls in the category of the x-ray transients that are observed in the low/hard state throughout the outburst .
We discuss the physical scenario of the low/hard state outburst for this source .