We consider current state of star formation theory and requirements to observations in millimeter and submillimeter ranges which are necessary for resolution of the most actual problems of the physics of star formation. Two key features of star-forming regions which define observational requirements to their studies, are relatively low energy of processes that take place there and smallness of corresponding spatial scales. This is especially true for the objects in the latest stages of ``pre-stellar'' evolution, that is, hot cores, hyper- and ultracompact HII regions, and protoplanetary disks. Angular resolution, sensitivity, and spectral coverage in existing projects of ground-based and space telescopes of submillimeter and millimeter range are not completely adequate to necessary requirements. To obtain detailed information on star-forming regions as well as on individual protostars it is necessary to employ a space-based interferometer.
Observations made using COBE, SCUBA, ISO and MAMBO have provided a reasonable working knowledge of both the intensity of the submm and far-infrared background radiation and the source counts of luminous high-redshift dusty galaxies. However, because there are uncertainties in the background intensity determinations, the samples of detected galaxies are small, and most importantly, their redshift distributions are very incomplete, details of the evolution of dusty galaxies remain unresolved. The next steps forward in the field will be the launches of SIRTF and ASTRO-F, the commissioning of SOFI…
Despite theoretical predictions of the existence of many submillimeter masers, and some pioneering observational discoveries over the past few decades, these lines have remained relatively unstudied due to (i) challenges associated with observing at shorter wavelength; and, (ii) lack of possibility of high (< 14'' at 345 GHz) angular resolution observations. With the advent of the SMA, the first submillimeter imaging array capable of sub-arcsecond resolution, APEX, and the promise of ALMA, opportunities are opening for performing new science with millimeter/submillmeter masers. In this talk, I…
Studying the physical environments of low mass and high mass cores using dust continuum emission provides important observational constraints on theoretical models of star formation. The motivation and procedure for modeling dust continuum emission is reviewed and the results of recent surveys towards low mass and high mass star forming regions are compared.
We investigate what we can learn about galaxy formation and evolution from the data which will be obtained by the forthcoming large submillimeter/millimeter facilities, mainly by the Atacama Submillimeter Telescope Experiment (ASTE) and the Atacama Large Millimeter Array/Large Millimeter and Submillimeter Array (ALMA/LMSA). We first calculate the source counts from 350 um to 3 mm using the empirical infrared galaxy number count model of Takeuchi et al. (2001). Based on the number counts, we evaluate the source confusion and determine the confusion limit at various wavebands as a function of th…
The strength of the submillimeter background light shows directly that much of the energy radiated by star formation and AGN is moved to far infrared wavelengths. However, it is only as this background at 850 microns has been resolved with direct submillimeter imaging that we have seen that it is created by a population of ultraluminous (or near ultraluminous) infrared galaxies (ULIGs) which appear to lie at relatively high redshifts (z>1). Mapping the redshift evolution of this major portion of the universal star formation has been difficult because of the poor submillimeter spatial resolutio…
Using the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope, we have obtained rest frame mid-infrared spectroscopy of two bright submillimeter galaxies. SMMJ02399-0136 at z=2.81 shows a superposition of PAH emission features and a mid-infrared continuum, indicating significant and roughly equal contributions to its bolometric luminosity from star formation and from a Compton-thick AGN. We derive a new redshift of z=2.80 for MMJ154127+6616 from the IRS spectrum and find this object is dominated by starburst PAH emission. The rest frame mid- to far-infrared spectral energy distrib…
We report the detection of CO(3-2) emission from the submillimeter-selected hyperluminous galaxy SMM 02399-0136. This galaxy is the brightest source detected in the recent SCUBA surveys of the submillimeter sky. The optical counterpart of the submillimeter source has been identified as a narrow-line AGN/starburst galaxy at z=2.8. The CO emission is unresolved, theta < 5 arcsec, and is coincident in redshift and position with the optical counterpart. The molecular gas mass derived from the CO observations is 8x10^{10} h_{75}^{-2} M_{sun}, after correcting for a lensing amplification factor of 2…
The first unbiased surveys for high-redshift galaxies in the submillimeter (submm) and far-infrared (FIR) wavebands have been made over the last two years. When combined with the intensity of extragalactic background radiation in the same wavebands, we have a reasonable first view of the dust enshrouded Universe. Limited spatial resolution hampers the identification of the submm galaxies, and follow-up observations currently consume much larger amounts of telescope time than the initial submm-wave detections. Here the prospects for future submm/FIR surveys are discussed, highlighting the impor…
We present submillimeter continuum maps at 450 and 850 microns of a 12 x 8 arcminute region of the NGC 7538 high-mass star-forming region, made using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. We used an automated clump-finding algorithm to identify 67 clumps in the 450 micron image and 77 in the 850 micron image. Contrary to previous studies, we find a positive correlation between high spectral index, alpha, and high submillimeter flux, with the difference being accounted for by different treatments of the error beam. We interpret the higher sp…
The global star formation rate in high redshift galaxies, based on optical surveys, shows a strong peak at a redshift of z=1.5, which implies that we have already seen most of the formation. High redshift galaxies may, however, emit most of their energy at submillimeter wavelengths if they contain substantial amounts of dust. The dust would absorb the starlight and reradiate it as far-infrared light, which would be redshifted to the submillimeter range. Here we report a deep survey of two blank regions of sky performed at submillimeter wavelengths (450 and 850-micron). If the sources we detect…
Improving our understanding of the initial conditions and earliest stages of protostellar collapse is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. Observationally, there are two complementary approaches to this problem: (1) studying the structure and kinematics of prestellar cores observed prior to protostar formation, and (2) studying the structure of young (e.g. Class 0) accreting protostars observed soon after point mass formation. We discuss recent advances made in this area thanks to (sub)millimeter mapping observations with large …
We present the results of 450 and 850 micron continuum mapping of the HII region KR 140 using the SCUBA instrument on the JCMT. KR 140 is a small (5.7 pc diameter) HII region at a distance of 2.3+/-0.3 kpc. Five of the six IRAS point sources near KR 140 were mapped in this study. Our analysis shows that two of these IRAS sources are embedded late B type stars lying well outside the HII region, two are a part of the dust shell surrounding the HII region, and one is the combined emission from an ensemble of smaller sources unresolved by IRAS. We have discovered a number of relatively cold submil…
I review the prospects for studies of the advanced evolutionary stages of low-, intermediate- and high-mass stars by the JWST and concurrent facilities, with particular emphasis on how they may help elucidate the dominant contributors to the interstellar dust component of galaxies. Observations extending from the mid-infrared to the submillimeter can help quantify the heavy element and dust species inputs to galaxies from AGB stars. JWST's MIRI mid-infrared instrument will be so sensitive that observations of the dust emission from individual intergalactic AGB stars and planetary nebulae in th…
Understanding of star formation in the Universe is advancing through submillimeter-wave observations of the Milky Way and other galaxies. Technological constraints on such observations require a mixture of telescope sizes and observational techniques. For some purposes, small submillimeter-wave telescopes are more sensitive than large ones. The Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) is a small, wide-field instrument located at an excellent observatory site. By observing the Milky Way and Magellanic Clouds at arcminute resolution, it provides a context for interpretin…
We have modeled the emission from dust in pre-protostellar cores, including a self-consistent calculation of the temperature distribution for each input density distribution. Model density distributions include Bonnor-Ebert spheres and power laws. The Bonnor-Ebert spheres fit the data well for all three cores we have modeled. The dust temperatures decline to very low values ($\Td \sim 7$ K) in the centers of these cores, strongly affecting the dust emission. Compared to earlier models that assume constant dust temperatures, our models indicate higher central densities and smaller regions of re…
We present deep submillimeter imaging of two spectroscopically confirmed z~6.5 Lyman-alpha emitters (LAEs) in the Subaru Deep Field. Although we reach the nominal confusion limit at 850 micron, neither LAE is detected at 850 micron nor 450 micron, thus we conclude that the LAEs do not contain large dust masses (<2.3e8 Msun and <5.7e8 Msun). The limit on their average L(FIR)/L(UV) ratios (<~35) is substantially lower than seen for most submillimeter selected galaxies at z~3, and is within the range of values exhibited by Lyman-break galaxies. We place upper-limits on their individual star forma…
We present a high spatial resolution submillimeter continuum survey of 24 circumstellar disks in the Tau-Aur and Oph-Sco star formation regions using the SMA. In the context of a simple model, we use broadband SEDs and submillimeter visibilities to derive constraints on some basic parameters that describe the structure of these disks. For the typical disk in the sample we infer a radial surface density distribution Σ~ r^-p with a median p ~ 0.5, although consideration of the systematic effects of some of our assumptions suggest that steeper distributions with p ~ 0.7-1.0 are more reasonable. T…
The results of the first generation of submillimeter-wave surveys have been published. The opening of this new window on the distant Universe has added considerably to our understanding of the galaxy formation process, by revealing a numerous population of very luminous distant galaxies. Most would have been very difficult to identify using other methods. The potential importance of selection effects, especially those connected with the spectral energy distributions of the detected galaxies, for the interpretation of the results are highlighted.
We present a census of the population of deeply embedded young stellar objects (YSOs) in the Ophiuchus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the "Cores to Disks" (c2d) legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. We have applied a method developed for identifying embedded protostars in Perseus to these datasets and in this way construct a relatively unbiased sample of 27 candidate embedded protostars with envelopes more massive than our sensitivity limit (about 0.1 M_sun). Embedded YSOs are found in 35% of the …
We present a census of the population of deeply embedded young stellar objects (YSOs) in the Perseus molecular cloud complex based on a combination of Spitzer Space Telescope mid-IR data from the c2d legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. The mid-IR sources detected at 24 micron and having [3.6]-[4.5] > 1 are located close to the center of the SCUBA cores, typically within 15" of their peaks. The narrowness of the spatial distribution of mid-IR sources around the peaks of the SCUBA cores suggests that no significant dispersal of the newly formed YSOs has occurred…
The correlation, found in nearby galaxies, between black hole mass and stellar bulge mass implies that the formation of these two components must be related. Here we report submillimeter photometry of eight x--ray absorbed active galactic nuclei which have luminosities and redshifts characteristic of the sources that produce the bulk of the accretion luminosity in the universe. The four sources with the highest redshifts are detected at 850 microns, with flux densities between 5.9 and 10.1 milliJanskies, and hence are ultraluminous infrared galaxies. Interpreting the submillimeter flux as emis…
We present a detailed analysis of the spatially-resolved properties of the lensed submillimeter galaxy SMMJ14011+0252 at z=2.56, combining deep near-infrared integral-field data obtained with SPIFFI on the VLT with other multi-wavelength data sets. The broad characteristics of SMMJ14011+0252 are in agreement with what is expected for the early evolution of local massive spheroidal galaxies. From continuum and line flux, velocity, and dispersion maps, we measure the kinematics, star-formation rates, gas densities, and extinction for individual subcomponents. The star formation intensity is simi…
We present the first comprehensive search for submillimeter and radio emission from the host galaxies of twenty well-localized gamma-ray bursts (GRBs). With the exception of a single source, all observations were undertaken months to years after the GRB explosions to ensure negligible contamination from the afterglows. We detect the host galaxy of GRB 000418 in both the sub-mm and radio, and the host galaxy of GRB 000210 only in the sub-mm. These observations, in conjunction with the previous detections of the host galaxies of GRB 980703 and GRB 010222, indicate that about 20% of GRB host gala…
We use new deep near-infrared (NIR) and mid-infrared (MIR) observations to analyze the 850$~μ$m image of the GOODS HDF-N region. We show that much of the submillimeter background at this wavelength is picked out by sources with $H(AB)$ or 3.6um (AB)<23.25 (1.8 uJy). These sources contribute an 850um background of 24\pm2 Jy deg^-2. This is a much higher fraction of the measured background (31-45 Jy deg^-2) than is found with current 20cm or 24um samples. Roughly one-half of these NIR-selected sources have spectroscopic identifications, and we can assign robust photometric redshifts to nearly al…
A major goal of modern astrophysics is to understand the processes by which the universe evolved from its initial simplicity, as seen in measurements of the Cosmic Microwave Background, to the universe we see today, with complexity on all scales. While the diffuse background measurements of COBE reveal the importance of the far infrared and submillimeter in early galaxy and star formation, the understanding of the development of complex structure requires high resolution imaging and spectroscopy. We present a concept for a space mission called SPECS, the Submillimeter Probe of the Evolution of…
We have carried out a submillimeter continuum and spectroscopic study of the W43 main complex, a massive star-forming region, which harbors a giant HII region. The maps reveal a filamentary structure containing ~50 fragments with masses of 40-4000 Msun and typical diameters of 0.25 pc. Their large sizes, large non-thermal velocities (Dv ~ 5 km/s), and high densities (n_H2 ~ 10^6 cm^-3) suggest that they are protoclusters and excellent sites to form massive stars. Follow-up observations are necessary, but we have already identified three protoclusters to be very good candidates for containing v…
We have modeled the emission of H2O rotational lines from the extreme C-rich star IRC+10216. Our treatment of the excitation of H2O emissions takes into account the excitation of H2O both through collisions, and through the pumping of the nu2 and nu3 vibrational states by dust emission and subsequent decay to the ground state. Regardless of the spatial distribution of the water molecules, the H2O 1_{10}-1_{01} line at 557 GHz observed by the Submillimeter Wave Astronomy Satellite (SWAS) is found to be pumped primarily through the absorption of dust-emitted photons at 6 $μ$m in the nu2 band. As…
We present observations of the luminous population of high-redshift sub-mm galaxies taken at the OVRO Millimeter Array. Studies of sub-mm galaxies are vital to our understanding of the formation and early evolution of galaxies since this population could account for a significant fraction of the total amount of star formation and AGN activity at high redshift. We discuss the CO detections for SMM J02399-0136 at z=2.8 and SMM J14011+0252 at z=2.6. The CO data show the presence of massive molecular gas reservoirs (M(H2) few X 10^{10}-10^{11} M(sun)) and suggest that the sub-mm galaxies are simil…
We investigate the mass function of cold, dusty clumps in 11 low- and high-mass star-forming regions. Using a homogeneous fitting technique, we analyze the shape of each region's clump mass function and examine the commonalities among them. We find that the submillimeter continuum clump mass function in low-mass star-forming regions is typically best fit by a lognormal distribution, while that in high-mass star-forming regions is better fit by a double power law. A single power law clump mass distribution is ruled out in all cases. Fitting all of the regions with a double power law, we find th…
I discuss our ongoing Owens Valley Millimeter Array observations and Keck near-infrared wavelength observations of the high-redshift sub-mm population of galaxies. These observations are important for our understanding of the distant universe since the sub-mm population accounts for a large fraction of the extragalactic background at mm/sub-mm wavelengths and contributes significantly to the total amount of star-formation and AGN activity at high redshift. The CO data suggest that the sub-mm galaxies are analogous to the gas-rich ultraluminous systems found in the local universe. Initial near-…
We have mapped an approximately 5.5 by 5.5 pc portion of the M17 massive star-forming region in both 850 and 450 micron dust continuum emission using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). The maps reveal more than 100 dusty clumps with deconvolved linear sizes of 0.05--0.2 pc and masses of 0.8--120 solar masses, most of which are not associated with known mid-infrared point sources. Fitting the clump mass function with a double power law gives a mean power law exponent of alpha_high = -2.4 +/- 0.3 for the high-mass power law, consist…
We present the results of the first detailed millimeter and submillimeter molecular line survey of bright rimmed clouds, observed at FCRAO in the CO (J=1-0), C18O (J=1-0), HCO+ (J=1-0), H13CO+ (J=1-0), and N2H+ (J=1-0) transitions, and at the HHT in the CO (J=2-1), HCO+ (J=3-2), HCO+ (J=4-3), H13CO+ (J=3-2), and H13CO+ (J=4-3) molecular line transitions. The source list is composed of a selection of bright rimmed clouds from the catalog of such objects compiled by Sugitani et al. (1991). We also present observations of three Bok globules done for comparison with the bright rimmed clouds. We fi…
We have obtained spectroscopic redshifts using the Keck-I telescope for a sample of 73 submillimeter (submm) galaxies for which precise positions are available. The galaxies lie at redshifts out to z=3.6, with a median redshift of 2.2. The dust-corrected ultraviolet (UV) luminosities of the galaxies rarely hint at their huge bolometric luminosities indicated by their radio/submm emission, underestimating the true luminosity by a median factor of ~100 for SMGs with pure starburst spectra. The 850mu, radio, and redshift data is used to estimate the dust temperatures (<Td>=36+-7 K), and character…
Observations at far-infrared and submillimeter wavelengths promise to revolutionize the study of high redshift galaxies and AGN by providing a unique probe of the conditions within heavily extinguished regions of star formation and nuclear activity. Observational capabilities in this spectral region will expand greatly in the next decade as new observatories are developed both in space and on the ground. These facilities include the Space Infrared Telescope Facility (SIRTF), the far-infrared and submillimeter telescope (FIRST), and the millimeter array (MMA). In the longer term, the requiremen…
We present results from the observations and modeling of seventeen Class I cores with the Submillimetre Common Users Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). By modeling the transfer of radiation through the envelope for nine cores, we find, for a power law distribution n(r)=n_f(r/r_f)^-p, the average and standard deviation p=1.6 +/- 0.4 and a median of p=1.8. However, the inclusion of a disk or other point-like component can cause the derived p to be shallower by as much as 0.5. In addition, we test the Shu collapse model for our sources and discuss the application…
We present deep mid-infrared spectroscopy with the Spitzer Space Telescope of 13 submillimeter galaxies (SMGs) in the Great Observatories Origins Deep Survey North (GOODS-N) field. We find strong polycyclic aromatic hydrocarbon (PAH) emission in all of our targets which allows us to measure mid-IR spectroscopic redshifts and place constraints on the contribution from star formation and active galactic nuclei (AGN) activity to the mid-IR emission. In the high signal-to-noise ratio composite spectrum of SMGs, we find that the hot dust continuum from an AGN contributes at most 30% of the mid-IR l…
We present new data obtained with the Submillimeter Array for a sample of fourteen nearby luminous and ultraluminous infrared galaxies. The galaxies were selected to have luminosity distances D < 200 Mpc and far-infrared luminosities log(L_FIR) > 11.4. The galaxies were observed with spatial resolutions of order 1 kpc in the CO J=3-2, CO J=2-1, 13CO J=2-1, and HCO+ J=4-3 lines as well as the continuum at 880 microns and 1.3 mm. We have combined our CO and continuum data to measure an average gas-to-dust mass ratio of 120 +/- 28 (rms deviation 109) in the central regions of these galaxies, very…
We present new multiwavelength submillimeter continuum measurements of the circumstellar dust around 48 young stars in the $ρ$ Ophiuchus dark clouds. Supplemented with previous 1.3 mm observations of an additional 99 objects from the literature, the statistical distributions of disk masses and submillimeter colors are calculated and compared to those in the Taurus-Auriga region. These basic submillimeter properties of young stellar objects in both environments are shown to be essentially identical. As with their Taurus counterparts, the $ρ$ Oph circumstellar dust properties are shown to evolve…
Using the ISOPHOT Serendipity Survey (ISOSS) at 170um a sample of galactic star-forming regions exhibiting very cold dust temperatures (< 20 K) and high masses (> 100 M_sun) has been established. We characterise the star-forming content of five regions that were selected as potential sites for early stage high-mass star formation using SCUBA (JCMT) and Spitzer observations. In every region we identify one to four submillimeter clumps with projected sizes between 0.1 and 0.4 pc. The dust temperatures range from 11.6 to 21.3 K and the estimated clump masses are 2 to 166 M_sun. Towards the majori…
Imaging and spectroscopic observations in the mid-infrared wavelength range (5$μ$m--30$μ$m) offer valuable insight into the origins of stars and planets. Sensitive new array detectors on 8-meter class telescopes make it possible to study a wide range of phenomena, from protoplanetary disks to starburst galaxies, in unprecedented detail. I review the capablities of ground-based mid-infrared instruments (e.g., high spatial resolution) and their limitations (e.g., poor sensitivity, small field of view) using several examples in the field of star formation, and discuss prospects for the near futur…
We report IRAM Plateau de Bure, millimeter interferometry of three z=~2.4 to 3.4, SCUBA deep field galaxies. Our CO line observations confirm the rest-frame UV/optical redshifts, thus more than doubling the number of confirmed, published redshifts of the faint submillimeter population and proving their high-z nature. In all three sources our measurements of the intrinsic gas and dynamical mass are large (1e10 to 1e11 Msun). In at least two cases the data show that the submillimeter sources are part of an interacting system. Together with recent information gathered in the X-ray, optical and ra…
The existence of supermassive collapsed objects in the cores of most galaxies poses still-unanswered questions. First, how did they form, and how does their mass depend on the properties of the host galaxy? Second, can observations probe the metric in the strong-field domain, testing whether it indeed agrees with the Kerr geometry predicted by general relativity (and, if so, what the spin is)?
We report on a deep search for CO(J=3-2) line emission from the host galaxy of GRB 980425 with the Atacama Submillimeter Telescope Experiment (ASTE). We observed five points of the galaxy covering the entire region. After combining all of the spectra, we obtained a global spectrum with the rms noise level of 3.3 mK in T_mb scale at a velocity resolution of 10 km s^-1. No significant emission was detected, though we find a marginal emission feature in the velocity range corresponding to the redshift of the galaxy. We derive 3 sigma upper limits on the global properties: the velocity-integrated …
We have carried out the observations of the OMC-2 FIR 3/4 region with the NMA and ASTE in the H$^{13}$CO$^{+}$ (1--0), $^{12}$CO (3--2, 1--0), SiO ($v$=0, $J$=2--1), CS (2--1), and CH$_3$OH ($J_K$=7$_K$--6$_K$) lines and in the 3.3 mm continuum emission. Our NMA observations in the H$^{13}$CO$^{+}$ emission have revealed 0.07 pc-scale dense gas associated with FIR 4. The $^{12}$CO (3--2,1--0) emission shows high-velocity blue and red shifted components at the both north-east and south-west of FIR 3, suggesting a molecular outflow nearly along the plane of the sky driven by FIR 3. The SiO and t…
We present results of submillimeter observations of a low-mass young stellar objects (YSOs) condensation in the Cederblad 110 region of the Chamaeleon I dark cloud with Atacama Submillimeter Telescope Experiment. Our HCO+(J=4-3) map reveals a dense molecular gas with an extent of ~ 0.1 pc, which is a complex of two envelopes associated with class I sources Ced110 IRS4 and IRS11 and a very young object Cha-MMS1. The other two class I sources in this region, IRS6 and NIR89, are located outside the clump and have no extended HCO+ emission. HCO+ abundance is calculated to be 2.6 x 10^{-10} for MMS…
The recently discovered Submillimeter Extragalactic Background (submm EB) has opened new perspectives on our understanding of galaxy evolution. We detail in this paper one of the major cosmological consequences of this discovery, the submm luminosity density history of the Universe.
We have mapped with the French submillimeter balloon-borne telescope ProNaOS the thermal emission of the dust in the M42 Orion Nebula. The map obtained is 50' by 40' with an angular resolution of about 3' in the four efficient wavelengths 200 $\mic$, 260 $\mic$, 360 $\mic$ and 580 $\mic$. The temperature and index we obtain are highly variable within the studied region: the temperature varies from 12 K to 70 K, and the spectral index from 1.1 to 2.2. The statistical analysis of the temperature and spectral index spatial distribution in this region, as well as in the other regions mapped by Pro…
Millimeter and mid-infrared observations have been made of the dense clumps of dust and gas and of young stellar objects (YSOs) associated with the bright, compact submillimeter source G79.3+0.3 P1 in the relatively nearby MSX infrared-dark cloud G79.3+0.3. The Gemini mid-infrared observations reported here indicate the presence of three YSOs within the cloud. BIMA 3 mm continuum observations show that the brightest of the YSOs is likely to be a Herbig Ae/Be star. High-angular-resolution molecular-line observations suggest that a wind from this star may be triggering collapse in the adjacent m…
Seven Class 0 sources mapped with SCUBA at 850 and 450 micron are modeled using a one dimensional radiative transfer code. The modeling takes into account heating from an internal protostar, heating from the ISRF, realistic beam effects, and chopping to model the normalized intensity profile and spectral energy distribution. Power law density models, n(r) ~ r^{-p}, fit all of the sources; best fit values are mostly p = 1.8 +/- 0.1, but two sources with aspherical emission contours have lower values (p ~ 1.1). Including all sources, <p> = 1.63 +/- 0.33. Based on studies of the sensitivity of th…
A spectral-line survey of IRC+10216 in the 345 GHz band has been undertaken with the Submillimeter Array. Although not yet completed, it has already yielded a fairly large sample of narrow molecular emission lines with line-widths indicating expansion velocities of ~4 km/s, less than 3 times the well-known value of the terminal expansion velocity (14.5 km/s) of the outer envelope. Five of these narrow lines have now been identified as rotational transitions in vibrationally excited states of previously detected molecules: the v=1, J=17--16 and J=19--18 lines of Si34S and 29SiS and the v=2, J=7…
We have obtained 850 and 450 micron continuum maps of 21 low mass cores with SED's ranging from pre-protostellar to Class I (18K < Tbol < 370K), using SCUBA at the JCMT. In this paper we present the maps, radial intensity profiles, and photometry. Pre-protostellar cores do not have power-law intensity profiles, whereas the intensity profiles of Class 0 and Class I sources can be fitted with power laws over a large range of radii. A substantial number of sources have companion sources within a few arcminutes (2 out of 5 pre-protostellar cores, 9 out of 16 Class 0/I sources). The mean separation…
The question "How did we get here and what will the future bring?" captures the human imagination and the attention of the National Academy of Science's Astronomy and Astrophysics Survey Commitee (AASC). Fulfillment of this "fundamental goal" requires astronomers to have sensitive, high angular and spectral resolution observations in the far-infrared/submillimeter (far-IR/sub-mm) spectral region. With half the luminosity of the universe and vital information about galaxy, star and planet formation, observations in this spectral region require capabilities similar to those currently available o…
We report our recent progress on extragalactic spectroscopic and continuum observations, including HCN(J=1-0), HCO$^+$(J=1-0), and CN(N=1-0) imaging surveys of local Seyfert and starburst galaxies using the Nobeyama Millimeter Array, high-J CO observations (J=3-2 observations using the Atacama Submillimeter Telescope Experiment (ASTE) and J=2-1 observations with the Submillimeter Array) of galaxies, and $λ$ 1.1 mm continuum observations of high-z violent starburst galaxies using the bolometer camera AzTEC mounted on ASTE.
We present here the continuum submillimeter maps of the molecular cloud around the M42 Nebula in the Orion region. These have been obtained in four wavelength bands (200, 260, 360 and 580 microns) with the ProNaOS two meter balloon-borne telescope. The area covered is 7 parsecs wide (50 arcmin at a distance of 470 pc) with a spatial resolution of about 0.4 parsec. Thanks to the high sensitivity to faint surface brightness gradients, we have found several cold condensations with temperatures ranging from 12 to 17 K, within 3 parsecs of the dense ridge. The statistical analysis of the temperatur…
Using a combination of radio and optical imaging at 0.1\arcs to 0.2\arcs resolution with the VLA/MERLIN and HST has led to a breakthrough in our understanding of radio emission from distant (0.1<z<3) starburst galaxies. We have recently isolated a number of high redshift, dusty starburst galaxies that remain invisible in ground based images to I_{AB}=25 and I_{AB}=28.5 in the Hubble Deep Field. These galaxies appear as faint radio sources, often accompanied by very red counterparts (I-K > 4-6) and submillimeter sources with S > 2 mJy at 850 microns as measured with SCUBA on the JCMT. The far-i…
We show that large, high-redshift (z>10) galaxies with virial temperature in excess of 10^4K may be mostly comprised of cold atomic clouds which were formerly minihalos. These clouds move at a speed of 15-30km/s and collide with one another on a time scale of 10^7yr. The supersonic collisions result in spatially distributed star formation with high efficiency. We then show that most, subsequent star formation in cold atomic clouds may be triggered by shockwaves launched from the first stars formed in collisions. Those shockwave-compressed clouds are even more widespread spatially because of la…
We present {\it Spitzer} images of the relatively sparse, low luminosity young cluster L988e, as well as complementary near-infrared (NIR) and submillimeter images of the region. The cluster is asymmetric, with the western region of the cluster embedded within the molecular cloud, and the slightly less dense eastern region to the east of, and on the edge of, the molecular cloud. With these data, as well as with extant H$α$ data of stars primarily found in the eastern region of the cluster, and a molecular $^{13}$CO gas emission map of the entire region, we investigate the distribution of formi…
High dynamic range imaging of submillimeter dust emission from the envelopes of eight young protostars in the Taurus and Perseus star-forming regions has been carried out using the SCUBA submillimeter camera on the James Clerk Maxwell Telescope. Good correspondence between the spectral classifications of the protostars and the spatial distributions of their dust emission is observed, in the sense that those with cooler spectral energy distributions also have a larger fraction of the submillimeter flux originating in an extended envelope compared with a disk. This results from the cool sources …
We present a study of the submillimeter (submm) emission of Distant Red Galaxies (DRGs). The DRGs are selected by the criterion (J-K)>2.3, and are generally massive galaxies at redshifts higher than 2, with red rest-frame optical colors. Using a deep SCUBA submm image of a field centred on the cluster MS1054-03, we obtain a statistical detection of the DRGs at redshift z=2-3.5, with an average 850um flux density of 1.11+-0.28mJy. The detection implies an average star formation rate (SFR) of 127+-34 M_sun/yr (lensing corrected), assuming that the far-infrared (FIR) spectral energy distribution …
