The NGC 4410 galaxy group contains five major galaxies in its inner regions, at least four of which appear to be connected in some way. Here is a smoothed 0.3 - 8 keV X-ray map of the inner portion of the NGC 4410 group from the Chandra X-ray Telescope (color), after it has been divided by a smoothed weighted exposure map (from Smith et al. 2003, in preparation). The yellow/white regions are brightest in X-rays, the red fainter, and the blue faintest. The black region outside of the blue rectangular area was not observed by Chandra. The contours are from the optical Digitized Sky Survey. (from Smith et al. 2003, Astronomical Journal, 126, 1763).

The five galaxies in the inner part of this group are labeled in the pictures below, which is an optical R-band image from the Southeastern Association for Research in Astronomy (SARA) 0.9m telescope. This image is displayed with two different stretches. In the first picture below, the stretch is such that the two galaxies NGC 4410 A+B are each visible. In the second picture, the stretch is set such that the faint bridges connecting NGC 4410A+B with NGC 4410C and NGC 4410D are visible, as well as the long tail extending to the southeast of NGC 4410A+B. The field of view in these images is about 6.7 arcminutes by 6.3 arcminutes. North is up and east is to the left.

Here is a close-up view of NGC 4410A+B, showing a ring-like structure in NGC 4410A, the galaxy on the right (west) (from Donahue, Smith, and Stocke 2002, Astronomical Journal, 123, 1922). The left image is a red continuum image, the right image is an image obtained with a narrowband filter containing the 6583 Angstrom hydrogen alpha line. This image shows the location of the ionized interstellar gas in this system. The bright clumps in the ring are HII regions. Notice the extremely bright HII region southeast of the NGC 4410A nucleus. The field of view is about 0.8 arcminutes X 1.1 arcminutes. These images were obtained by Megan Donahue on the 2.1m telescope at the Kitt Peak National Observatory in Arizona.

Here is a very close-up optical image of NGC 4410A (below), from the Hubble Space Telescope. The field of view is 34"; north is up and east is to the west. Notice the ring-like structure to the northwest, and the knots of star formation on the eastern section of the ring and the especially bright knot to the south of the nucleus. NGC 4410B is at the edge of the image, to the west.

Here is an expanded view of the 0.3 - 8 keV Chandra image near NGC 4410A+B. The bright peak is at the nucleus of NGC 4410A. The secondary peak to the east is at the nucleus of NGC 4410B. The extension to the northwest is coincident with the northwestern filament of ionized gas, which has an optical spectrum suggestive of shock ionization.

Here is an overlay of the H-alpha image (contours) on the Chandra image (colors). Notice the coincidence of the X-ray and H-alpha extension to the northeast, as well as the similar morphology near the NGC 4410A nucleus. Notice that the HII regions do NOT have obvious X-ray counterparts.

In the next picture, the optical Digitized Sky Survey. image of the inner part of the NGC 4410 group is shown, with circles plotted showing the location of X-ray point sources found in the Chandra data. Two of these sources, labeled 2 and 5 in this picture, have optical counterparts. These may be background active galaxies. Sources 3 and 8 have large number of high-energy X-ray photons compared to those at lower energies, suggesting that they may also be background objects. If the remaining sources, 1, 4, 6, and 7, are associated with the NGC 4410 group, they would be classified as `Ultraluminous X-Ray Sources' (ULXs), with X-ray luminosities greater than or equal to 10³⁹ erg/s. This is much higher than typical X-ray binaries in the Milky Way, which are thought to contain stellar black holes (masses of about 10 times that of the Sun). ULXs are thought to be either intermediate mass black holes (about 100 times the mass of the Sun or more), or else stellar mass black holes with jets aimed towards us.

In the following larger field of view image, contours showing the location of the interstellar atomic hydrogen gas are superposed on the SARA optical image of the inner part of the NGC 4410 group, including NGC 4410A, B, C, D, and F. NGC 4410A+B, D, and F are detected in HI. NGC 4410A+B and D both have tail-like HI structures, coincident with stellar tails. HI is detected via the 21 cm radio line. These data were obtained with the Very Large Array, part of the National Radio Astronomy Observatory (from B. J. Smith 2000, Astrophysical Journal, 541, 624).

NGC 4410A, the ring-like galaxy, was also detected in the 2.6mm line of carbon monoxide, showing that molecular gas is very abundant in this galaxy. The CO spectrum shown below was obtained with the NRAO 12 meter telescope on Kitt Peak in Arizona.

A much larger field of view image of the NGC 4410 group is shown below. The grey scale is the Digitized Sky Survey optical image; the contours are the 21 cm HI map from the Very Large Array. Seven galaxies in this group were detected in HI; these galaxies are labeled. The increased noise at the edge of the HI map is due to decreased sensitivity at the edges of the primary beam. The two optically-bright galaxies near the bottom of the image are NGC 4411 and NGC 4411B (west and east, respectively). These are foreground galaxies in the Virgo Cluster, and are not in the observed HI velocity range.

NGC 4410A is a radio galaxy, with two large lobes visible in radio continuum maps. The next image is a 20 centimeter radio continuum map of the NGC 4410 group (contours; from the Very Large Array), superposed on the optical Digitized Sky Survey image (greyscale). Note the two large radio structures, one extending 200 kpc to the north, the other 80 kpc to the south. These lobes are presumably caused by electrons and protons being ejected at high speeds from the vicinity of a massive black hole in the center of the galaxy. The southern lobe may been distorted by a collision with the atomic hydrogen gas in the tidal tail. A higher spatial resolution radio continuum map of this system can be found in Hummel et al. (1986), A+A, 155, 161.

To see more Chandra images of this system in different energy ranges, click here.

To see how different assumptions in making the exposure map affects the final Chandra image, click here.

To return to Beverly Smith's home page, click here
To look at my poster on NGC 4410 from the Gas and Galaxy Evolution Conference, click here.
To read my conference proceedings for that meeting, click here.
To read my paper on the atomic and molecular interstellar gas in the NGC 4410 galaxy group (Smith 2000, Ap. J., 541, 624), click here.
To read the Donahue, Smith, and Stocke paper on star formation in NGC 4410A+B, click here. (2002, AJ, 123, 1922).
To read the Smith et al. (2003, AJ, 126, 1763) paper on the Chandra observations of NGC 4410, click here.
To see our Chandra results on the interacting galaxy pair NGC 7714/5 (Arp 284), click here, and to read the paper, click here.

Last updated: 2/10/05