Chandra observations of NGC 4438:: An environmentally damaged galaxy in the Virgo cluster

We present results from a 25 ks Chandra ACIS-S observation of galaxies NGC 4438 and NGC 4435 in the Virgo Cluster. X-ray emission in NGC 4438 is observed in a similar to700 pc nuclear region, a similar to2.3 kpc spherical bulge, and a network of filaments extending 4-10 kpc to the west and southwest of the galaxy. The X-ray emission in all three regions is highly correlated to similar features observed in Halpha. Spectra of the filaments and bulge are well represented by a 0.4 keV MEKAL model with combined 0.3-2 keV intrinsic luminosity L-X 1.24 x 10(40) ergs s(-1), electron densities similar to0.02-0.04 cm(-3), cooling times of 400-700 Myr, and X- ray gas mass less than or similar to3.7 x 10(8) M-circle dot. In the nuclear region of NGC 4438 X- ray emission is seen from the nucleus and from two outflow bubbles extending 360 pc ( 730 pc) to the northwest (southeast) of the nucleus. The spectrum of the northwest outflow bubble plus nucleus is well fitted by an absorbed (n(H) = 1.9(-0.4)(+1.0) x 10(21) cm(-2)) 0.58(-0.10)(+0.04) keV MEKAL plasma model plus a heavily adsorbed (n(H) = 2.9(-2.0)(+3.1) x 10(22) cm(-2)) Gamma = 2, power-law component. The electron density, cooling time, and X- ray gas mass in the northwest outflow are similar to0.5 cm(-3), 30 Myr, and 3.5 x 10(6) M-circle dot, respectively. Weak X- ray emission is observed in the central region of NGC 4435 with the peak of the hard emission coincident with the galaxy's optical center, while the peak of the soft X- ray emission is displaced 316 pc to the northeast. The spectrum of NGC 4435 is well fitted by a nonthermal power law plus a thermal component from 0.2 - 0.3 keV diffuse interstellar medium gas. We argue that the X-ray properties of gas outside the nuclear region in NGC 4438 and NGC 4435 favor a high- velocity, off- center collision between these galaxies similar to100 Myr ago, while the nuclear X-ray-emitting outflow gas in NGC 4438 has been heated only recently (within similar to1-2 Myr) by shocks (v(s) similar to 600 km s(-1)) possibly powered by a central active galactic nucleus.