We present results of a sensitive 76 ksec Chandra observation of the young stellar cluster in NGC 2024 , lying at a distance of \sim 415 pc in the Orion B giant molecular cloud .
Previous infrared observations have shown that this remarkable cluster contains several hundred embedded young stars , most of which are still surrounded by circumstellar disks .
Thus , it presents a rare opportunity to study X-ray activity in a large sample of optically invisible protostars and classical T Tauri stars ( cTTS ) undergoing accretion . Chandra detected 283 X-ray sources of which 248 were identified with counterparts at other wavelengths , mostly in the near-infrared .
Astrometric registration of Chandra images against the Two Micron All Sky Survey ( 2MASS ) resulted in positional offsets of \approx 0.25 ^ { \prime \prime } near field center , yielding high confidence indentifications of infrared counterparts .
The Chandra detections are characterized by hard heavily-absorbed spectra and spectacular variability .
Spectral analysis of more than 100 of the brightest X-ray sources yields a mean extinction \langle A _ { V } \rangle \sim 10.5 mag and typical plasma energies \langle kT \rangle \sim 3 keV .
The range of variability includes rapid impulsive flares and persistent low-level fluctuations indicative of strong magnetic activity , as well as slow rises and falls in count rate whose origin is more obscure .
Some slowly-evolving outbursts reached sustained temperatures of kT \sim 6 - 10 keV . Chandra 
detected all but one of a subsample of 27 cTTS identified from previous near and mid-IR photometry , and their X-ray and bolometric luminosities are correlated .
We also report the X-ray detection of IRS 2b , which is thought to be a massive embedded late O or early B star that may be the ionizing source of NGC 2024 .
Seven millimeter-bright cores ( FIR 1-7 ) in NGC 2024 that may be protostellar were not detected , with the possible exception of faint emission near the unusual core FIR-4 .