A 96-ks Chandra X-ray observation of \rho Ophiuchus cloud core A detected 87 sources , of which 60 were identified with counterparts at other wavelengths .
The X-ray detections include 12 of 14 known classical T Tauri stars ( CTTS ) in the field , 15 of 17 known weak-lined TTS ( WTTS ) , and 4 of 15 brown dwarf candidates .
The X-ray detections are characterized by hard , heavily absorbed emission .
Most X-ray detections have visual extinctions in the range A _ { V } \approx 10 - 20 mag , but several sources with visual absorptions as high as A _ { V } \approx 40 - 56 mag were detected .
The mean photon energy of a typical source is \langle E \rangle \approx 3 keV , and more than half of the detections are variable .
Prominent X-ray flares were detected in the unusual close binary system Oph S1 , the X-ray bright WTTS DoAr 21 , and the brown dwarf candidate GY 31 ( M5.5 ) .
Time-resolved spectroscopic analysis of the DoAr 21 flare clearly reveals a sequence of secondary flares during the decay phase which may have reheated the plasma .
We find that the X-ray luminosity distributions and spectral hardnesses of CTTS and WTTS are similar .
We also conclude that the X-ray emission of detected brown-dwarf candidates is less luminous than T Tauri stars , but spectroscopically similar .

Simultaneous multifrequency VLA observations detected 31 radio sources at 6 cm , of which ten were also detected by Chandra .
We report new radio detections of the optically invisible IR source WLY 2-11 and the faint H \alpha emission line star Elias 24 ( class II ) .
We confirm circular polarization in Oph S1 and report a new detection of circular polarization in DoAr 21 .
We find no evidence that X-ray and radio luminosities are correlated in the small sample of TTS detected simultaneously with Chandra and the VLA .

We describe a new non-parametric method for estimating X-ray spectral properties from unbinned photon event lists that is applicable to both faint and bright X-ray sources .
The method is used to generate f _ { X } , \log T and L _ { X } light curves .
In addition , we provide a publically-available electronic database containing multi-wavelength data for 345 known X-ray , IR , and radio sources in the core A region .