The Infrared Space Observatory (ISO) is an ESA (European Space Agency) project with instruments funded by ESA member states (especially the PI countries France, Germany, The Netherlands and the United Kingdom) and with participation of ISAS (Japan) and NASA (USA). It was operated from November 1995 till May 1998, almost a year longer than expected. As an unprecedented observatory for infrared astronomy, able to examine cool and hidden places in the Universe, ISO successfully made nearly 30,000 scientific observations. The ISO Data Archive is available at the ISO Data Centre at https://www.cosmos.esa.int/web/iso it includes about 150,000 observations, if account is taken of calibration and parallel or serendipity mode observations. The catalogue contains all observations performed in standard observing modes exempt from technical problems; special flags indicate calibration observations. ISO helpdesk: https://support.cosmos.esa.int/iso/
The 170 micron far-infrared slew data of the ISOPHOT Serendipity Survey (ISOSS) has been assembled to a sky atlas with ~15% sky coverage. The redundant information of the brightnesss at slew crossings has been used to globally rescale and homogenize the slew brightnesses, leading to significantly increased photometric accuracy and reproducibility as well as the homogeneity of the maps. The corrected slew data were remapped with a constant grid size of 22.4arcsec onto 124 maps in galactic coordinates.
Due to the short timescales involved and observational difficulties, our knowledge of the earliest phases of massive star formation remains incomplete. We aim to explore the physical conditions during the initial phases of high-mass star formation and to detect a genuine massive (mass M>8M_{sun}_) protostar at an early evolutionary stage.
This paper presents results of JHKLM photometry data analysis of 249 southern 'IRAS-discovered' stars, which exhibit an emission feature at 11.3 microns in their low-resolution spectra (class 4n stars). The method of Epchtein et al. (1987A&AS...71...39E) is used to separate oxygen-rich and carbon-rich stars on the basis of their sole NIR and IRAS broad-band fluxes. It is shown that NIR data are necessary to calculate the total IR energy received from IRAS stars and such fundamental parameters as individual mass loss rates. An evolutionary model is developed to match the sequence of stars in color diagrams. It is suggested that the sequence of increasing optical depths might not be an evolutionary sequence, but would rather reflect the termination of a process in which the near-IR index increases very quickly at the beginning and is strongly dependent on the mass loss rate.
We present the results of a near-infrared monitoring programme of a selected sample of stars, initially suspected to be Mira variables and OH/IR stars, covering more than a decade of observations. The objects monitored cover the typical range of IRAS colours shown by O-rich stars on the asymptotic giant branch and show a surprisingly large diversity of variability properties. Sixteen objects are confirmed as large-amplitude variables.
RAFGL7009S is a deeply embedded massive young stellar objet (YSO) showing strong ice and saturated silicate absorption features in the mid infrared. It is associated with the ultracompact H II region G25.65+1.05, which may be excited by a B1V star. We have obtained JHK images of a 1' field centred on this YSO. In K we detect a non-resolved object coinciding with the radio continuum emission peak. Considering the high extinction towards this source (A_V_>=100mag), the observed K emission is more than 7~mag in excess of that expected for a B1V star. We suggest that this emission is mainly due to scattering of the central zone emission, as recently found for a sample of embedded massive YSOs associated with 3.1{mu}m H_2_O ice absorption (Ishii et al., 2002AJ....124..430I). We estimate the YSO's age to be 2x10^4^ years. The outflow, the methanol maser emission and the strong ice absorption features suggest the presence of a dense medium very close to the star, possibly a disk. The observations were obtained with the Montreal Near-IR Camera (MONICA, Nadeau et al., 1994PASP..106..909N) mounted at the F/8 Cassegrain focus of the 3.6-m Canada-France-Hawaii Telescope on 1996 July 1 UT. Frames were obtained through the J, H and K broad-band filters with total integration times of 840s, 160s and 100s Details about the instrumentation, the calibration and the data analysis can be found in Deharveng et al. (1999, Cat. <J/A+A/344/943>).
We present a multi-epoch infrared photometric study of the intermediate-mass star-forming region G173.58+2.45. Photometric observations are obtained using the near-infrared JHKL'M' filters and narrow-band filters centred at the wavelengths of the H_2_(1-0)S(1)(2.122um) and [FeII](1.644um) lines. The H2 image shows molecular emission from shocked gas, implying the presence of multiple star formation and associated outflow activity. We see evidence for several collimated outflows.
Our goal in this paper is to study stars and molecular gas in the direction of IRAS 06145+1455 (WB89-789). The kinematic distance of the associated molecular cloud is 11.9kpc. With a galactocentric distance of ~20.2kpc, this object is at the edge of the (molecular) disk of the Galaxy. We use near-IR (J, H, K), molecular line-, and dust continuum observations.
We present K-counts and JHK detailed photometry for a number of stars with K<=+9.0 in three clear regions near the galactic centre. These regions are all located approximately at l~0.0 and at latitudes b~-3.5,-4.0 and 4.5 respectively. Their Cumulative Counts Functions (CCF's) are formed, and with the aid of an exponential disk model for the Galaxy they are separated into disk and bulge CCF. As for the case in Baade's Window (BW) (Ruelas-Mayorga & Teague, 1992A&AS...95..379R) the disk is dominant at bright magnitudes whereas the bulge dominates at the faint end of the CCF. The slope of the bulge CCF is steeper than that for the disk in all three cases corroborating the result obtained for BW. The two colour JHK diagram and the K vs J-K diagram for the three regions show that the stellar population in these areas is similar to that studied in BW by us and by Frogel & Whitford (1987ApJ...320..199F). An average value of E(J-K)~0.42mag for the reddening is obtained, which is somewhat larger than that found for BW (0.27). Finally it is shown that at K<=+9.0, the disk population may be accounted for by those sources with J-K<=+1.6 whereas the bulge population presents values for J-K in excess of +1.6.
We report the detection of a curved magnetic field in the ring-like shell of the bubble N4, derived from near-infrared polarization of reddened diskless stars located behind this bubble. The magnetic field in the shell is curved and parallel to the ring-like shell, and its strength is estimated to be ~120{mu}G in the plane of the sky. The magnetic field strength in the shell is significantly enhanced compared to the local field strength. We calculate the mass-to-flux ratio for the submillimeter clumps in the shell and find that they are all magnetically subcritical. Our results demonstrate that the magnetic field strengthens as the interstellar medium is compressed into a shell, and suggest that the magnetic field has the potential to hinder star formation triggered by H II region expansion.
