In some cases, the coordinates listed for the entrance aperture do not correspond to the coordinates of the galaxy identified in the header as the target of the observation, and IUE did not, in fact, observe an object but rather sampled blank parts of the sky. The galaxies for which the spectra are clearly misplaced, and which were removed from the present catalog, are: MCG +06-20-0022, NGC 3077, NGC 5813, AOO 1204-137, AOO PKS 1543+091, AOO ACG 1116+51, and AOO POX 4. For all the galaxies of the sample but six, the representative spectrum presented was obtained by the matching procedure of the SW and LW spectra (see section 5). The additive constant eventually applied to the LW spectrum is included on the right side of the plot. The LW spectra of five galaxies: NGC 147, NGC 253, AOO GH 10-4, NGC 3642, NGC 6062, shows a rising trend toward short wavelengths; it is possible that an additional light source contributed to the recorded spectrum. The LW spectrum for these galaxies is presented without performing the matching procedure.
Below we provide a few comments on individual objects and for the galaxies for which more than one page is presented:
AOO UM 239: This object was rejected from the list of galaxies included in this guide. The IUE aperture is located on an object that is one arcmin south of the declination quoted by NED for AOO UM 239.
NGC 221: This companion of the Andromeda galaxy, in the Local Group, is one of the most observed elliptical galaxies. The CIV line is absent in the deepest image: SWP30289.
NGC 224: This is M31, a spiral galaxy in the Local Group where the IUE spectra sampled the bulge population at the center. The UV spectral energy distribution appears similar to that of an elliptical galaxy.
NGC 244: The single spectrum of this galaxy available in the archive, belongs actually to the galaxy NGC 224, according to the aperture coordinates.
IC 1613: The SW and LW images refer to different regions of the galaxy. Therefore, the corresponding spectra displayed in the figure are separated.
NGC 300: This very extended galaxy was removed from the list. Only one IUE spectrum was obtained for it, and it corresponds to a region at the outskirts of the galaxy, not to a specific significant region such as the photocenter.
NGC 1022: The signal of the SW spectrum is zero. No matching procedure was applied to the LW spectrum, for obvious reasons.
NCG 1617: Some pixels of the LW spectrum are saturated.
NGC 1705: Although some pixels of the LW spectrum are saturated, the final representative spectrum is reasonably smooth.
PG 0833+652: Some pixels of the LW spectrum are saturated.
MRK 116 A: This object is one of a pair of interconnected blue compact galaxies. As a low metallicity galaxy, it is a good target for studying the star formation history and chemical mixing process.
NGC 3034: This nuclear starburst galaxy, also known as M82, shows a bipolar outflow along its minor axis. The IUE aperture was located on its center and on two regions near the outflow, named BD+ 70 5888A KNOT A and BD+ 70 5888A KNOT B. This galaxy has been extensively studied at various wavelengths.
AOO GH 10-4: The coordinates listed for this galaxy are from NED.
AOO ACG 1116+51: The IUE coordinates of this target are wrong. The IUE
spectrograph missed the object, which is at 11
19
34
.24
+51
30' 11".84
(PMM USNO-A2.0). As explained above, this galaxy was excluded from
our compilation.
AOO 1214-277 and AOO 1214-28: These targets are near the Tololo 21 galaxy. The coordinates reported in the corresponding pages are those of some objects near the galaxy, listed in the PMM USNO-A2.0 catalog.
NGC 4449: Up to 48 spectra were obtained by IUE for NGC 4449. There are many HII regions and a complex of supernova remnants in this irregular galaxy. Eight pages are shown here for NGC 4449, representing the different regions sampled by IUE.
AOO ANON 1244-53: The level of the spectrum in the LW frame is consistent with a noisy zero signal.
NGC 4861: This system consists of IC 3961 plus a blue compact HII region in the south-west, identified as NGC 4861. Individual pages are shown for the two objects.
AOO POX 120: The declination quoted in LEDA is wrong. The coordinates listed here for this galaxy are from NED.
NGC 5236: This galaxy, better known as M83, is a nearby bright starburst spiral. Young massive star cluster systems are located in the nucleus and in the arms. Many IUE spectra were obtained at the position of some of the large number of historical supernovae observed in this galaxy.
NGC 5253: This nearby dwarf starburst galaxy hosts many bright knots embedded in its amorphous central region. It is believed that this complex of starburst regions is the source of the strong soft thermal X-ray emission detected by ROSAT. The representative spectrum is quite smooth, although the SW spectrum is saturated from 1800 to 1900Å.
NGC 5461 and NGC 5471: These are two HII regions in the outskirts of M101.
AOO PKS 1543+091: The IUE coordinates are wrong, and the spectrograph pointed at an unidentified faint object. The object is not included in our ``normal galaxies'' sample.
ESO B338-IG4: This is a compact galaxy with double nuclei that was extensively studied by IUE.
AOO AM 2020-504; The declination listed in LEDA is wrong. The coordinates presented here for this galaxy are from NED.
MCG-07-47-023: The signal in the SW and LW spectra is consistent with a noisy zero signal.
NGC 7673: The coordinates of the LW frame are outside the object. The correct location of the aperture, calculated from the position of the guide star as stored in the header of this image, is still outside the galaxy.