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Ly-alpha blobs (LABs) offer insight into the complex interface between galaxies and their circumgalactic medium. Whilst some LABs have been found to contain luminous star-forming galaxies and active galactic nuclei that could potentially power the Ly-alpha emission, others appear not to be associated with obvious luminous galaxy counterparts. It has been speculated that LABs may be powered by cold gas streaming on to a central galaxy, providing an opportunity to directly observe the `cold accretion' mode of galaxy growth. Star-forming galaxies in LABs could be dust obscured and therefore detectable only at longer wavelengths. We stack deep SCUBA-2 observations of the SSA22 field to determine the average 850um flux density of 34 LABs. We measure S_850 = 0.6 +/- 0.2mJy for all LABs, but stacking the LABs by size indicates that only the largest third (area > 1794 kpc^2) have a mean detection, at 4.5 sigma, with S_850 = 1.4 +/- 0.3mJy. Only two LABs (1 and 18) have individual SCUBA-2 > 3.5 sigma detections at a depth of 1.1mJy/beam. We consider two possible mechanisms for powering the LABs and find that central star formation is likely to dominate the emission of Ly-alpha, with cold accretion playing a secondary role., Accepted MNRAS 16 May 2016

Deep submillimeter (submm) continuum imaging observations of the starburst galaxy M82 are presented at 350, 450, 750 and 850 micron wavelengths, that were undertaken with the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope in Hawaii. The presented maps include a co-addition of submm data mined from the SCUBA Data Archive. The co-added data produce the deepest submm continuum maps yet of M82, in which low-level 850 micron continuum has been detected out to 1.5kpc, at least 10% farther in radius than any previously published submm detections of this galaxy. The overall submm morphology and spatial spectral energy distribution of M82 have a general north-south asymmetry consistent with H-alpha and X-ray winds, supporting the association of the extended continuum with outflows of dust grains from the disk into the halo. The new data raise interesting points about the origin and structure of the submm emission in the inner disk of M82. In particular, SCUBA short wavelength evidence of submm continuum peaks that are asymmetrically distributed along the galactic disk suggests the inner-disk emission is re-radiation from dust concentrations along a bar (or perhaps a spiral) rather than edges of a dust torus, as is commonly assumed. Higher resolution submm interferometery data from the Smithsonian Submillimeter Array and later Atacama Large Millimeter Array should spatially resolve and further constrain the reported dust emission structures in M82., Accepted by the Astronomical Journal -- 28 pages and 14 figures

We present total and polarized intensity images of 15 active galactic nuclei obtained with the Very Long Baseline Array at 7 mm at 17 epochs from 1998 March to 2001 April. At some epochs the images are accompanied by nearly simultaneous polarization measurements at 3 mm, 1.35/0.85 mm, and optical wavelengths. Here we analyze the 7 mm images to define the properties of the jets of two radio galaxies, five BL Lac objects, and eight quasars on angular scales $\gtrsim 0.1$ milliarcseconds. We determine the apparent velocities of 106 features in the jets; for many of the features we derive Doppler factors using a new method based on comparison of timescale of decline in flux density with the light-travel time across the emitting region. This allows us to estimate the Lorentz factors, intrinsic brightness temperatures, and viewing angles of 73 superluminal knots, as well as the opening angle of the jet for each source. We analyze the derived physical parameters of the jets. In nine sources we detect statistically meaningful deviations from ballistic motion, with the majority of components accelerating with distance from the core. In six sources we identify jet features with characteristics of trailing shocks that form behind the primary strong perturbations in jet simulations. The apparent speeds of these components increase with distance from the core suggesting an acceleration of the underlying jet., Comment: 100 pages, 44 figures, accepted for publication in AJ. This version does not contain figures 1-15,17(sequences of the images) due to very large size of the figures. The complete version (7mm_ms.ps) can be found at the website: www.bu.edu/blazars/multi.html

We report on submillimetre observations of three high redshift (z>6) quasars, made using the SCUBA camera on the JCMT. Only one of the sample was detected at 850um-- SDSS J1148+5251 (z=6.43). It was also detected (>3 sigma significance) at 450um, one of the few z>4 quasars for which this is the case. In combination with existing millimetric data, the submm detections allow us to place limits on the temperature of the submm-emitting dust, hence on the mass of dust to be synthesized under the time constraint imposed by the quasar's redshift., Comment: 5 pages, MNRAS, in press

We present multiwavelength observations of AO 0235+164 made during a 5 mag outburst in 1997. Detection of the outburst at the observatory of the South Eastern Association for Research in Astronomy prompted a concerted effort by several observatories to monitor the source in the R band. We present V-, R-, and I-band photometry, as well as contemporaneous 850 μm and X-ray measurements. We also use radio measurements from the University of Michigan's World Wide Web site in our analysis. We find that the source varies nearly simultaneously over 6 decades in frequency during this outburst and examine the possibility that the outburst was a result of a microlensing event. The duration of the outburst was on the order of 800 days, and the maximum luminosity was approximately 9.86 × 1047 ergs s-1 (assuming no relativistic beaming). We also analyze the long-term optical light curve and find that, although there is still no evidence for periodicity, the variations are interesting: the timescales between pairs of outbursts are remarkably similar. We suggest that the multifrequency behavior of the 1997 outburst is consistent with microlensing scenarios, while observations of previous outbursts suggest they were not consistent with gravitational microlensing.

From a combination of high quality X-ray observations from the NASA Rossi X-ray Timing Explorer (RXTE), and infrared observations from the UK Infrared Telescope (UKIRT) we show that the medium energy X-ray (3-20 keV) and near infrared fluxes in the quasar 3C273 are highly correlated. It is widely believed that the X-ray emission in quasars like 3C273 arises from Compton scattering of low energy seed photons and our observations provide the first reliable detection of correlated variations in 3C273 between the X-ray band and any lower energy band. For a realistic electron distribution we demonstrate that it is probable that each decade of the seed photon distribution from the mm to IR waveband contributes roughly equally to the medium energy X-ray flux. However the expected mm variations are too small to be detected above the noise, probably explaining the lack of success of previous searches for a correlation between X-ray and mm variations. In addition we show that the infrared leads the X-rays by 0.75+/-0.25 days. These observations rule out the `External Compton' emission process for the production of the X-rays., 7 pages, 5 figures. Uses mn style file and epsf. Accepted for publication in the MNRAS

Indirect detections of massive — presumably Jupiter-like — planets orbiting nearby Sun-like stars have recently been reported1,2. Rocky, Earth-like planets are much more difficult to detect, but clues to their possible existence can nevertheless be obtained from observations of the circumstellar debris disks of dust from which they form. The presence of such disks has been inferred3 from excess far-infrared emission but, with the exception of beta Pictoris4, it has proved difficult to image these structures directly as starlight dominates the faint light scattered by the dust5. A more promising approach is to attempt to image the thermal emission from the dust grains at submillimetre wavelengths6,7. Here we present images of such emission around Fomalhaut, beta Pictoris and Vega. For each star, dust emission is detected from regions comparable in size to the Sun's Kuiper belt of comets. The total dust mass surrounding each star is only a few lunar masses, so any Earth-like planets present must already have formed. The presence of the central cavity, approximately the size of Neptune's orbit, that we detect in the emission from Fomalhaut may indeed be the signature of such planets.

We mapped five massive star forming regions with the SCUBA-2 camera on the James Clerk Maxwell Telescope (JCMT). Temperature and column density maps are obtained from the SCUBA-2 450 and 850 $\mu$m images. Most of the dense clumps we find have central temperatures below 20 K with some as cold as 8 K, suggesting that they have no internal heating due to the presence of embedded protostars. This is surprising, because at the high densities inferred from these images and at these low temperatures such clumps should be unstable, collapsing to form stars and generating internal heating. The column densities at the clump centres exceed 10$^{23}$ cm$^{-2}$, and the derived peak visual extinction values are from 25-500 mag for $\beta$ = 1.5-2.5, indicating highly opaque centres. The observed cloud gas masses range from $\sim$ 10 to 10$^{3}$ M$_{\odot}$. The outer regions of the clumps follow an $r^{-2.36\pm0.35}$ density distribution and this power-law structure is observed outside of typically 10$^{4}$ AU. All these findings suggest that these clumps are high-mass starless clumps and most likely contain high-mass starless cores., Comment: Accepted for publication in AJ

We describe the capabilities of SCUBA-2, the first CCD-like imager for submillimeter astronomy, and the technologies that make it possible. Unlike previous detectors using discrete bolometers, SCUBA-2 has two dc-coupled, monolithic arrays with a total of ~10,000 bolometers. SCUBA-2’s absorber-coupled pixels use superconducting transition edge sensors operating at ~ 120mK for photon-noise limited performance and a SQUID time-domain multiplexer for readout. It will offer simultaneous imaging of an 8 × 8 arcmin field of view at wavelengths of 850 μm and 450 μm. SCUBA-2 is expected to have a huge impact on the study of galaxy formation and evolution in the early Universe as well as star and planet formation in our own Galaxy. Mapping the sky to the same S/N up to 1000 times faster than SCUBA, SCUBA-2 will also act as a pathfinder for submillimeter interferometers such as ALMA. SCUBA-2 will begin operation on the JCMT in 2006.

SCUBA-2 is an innovative 10,000 pixel submillimeter camera due to be delivered to the James Clerk Maxwell Telescope in late 2006. The camera is expected to revolutionize submillimeter astronomy in terms of the ability to carry out wide-field surveys to unprecedented depths addressing key questions relating to the origins of galaxies, stars and planets. This paper presents an update on the project with particular emphasis on the laboratory commissioning of the instrument. The assembly and integration will be described as well as the measured thermal performance of the instrument. A summary of the performance results will be presented from the TES bolometer arrays, which come complete with in-focal plane SQUID amplifiers and multiplexed readouts, and are cooled to 100mK by a liquid cryogen-free dilution refrigerator. Considerable emphasis has also been placed on the operating modes of the instrument and the common-user aspect of the user interface and data reduction pipeline. These areas will also be described in the paper., 15 pages; in Proceedings of Millimeter and Submillimeter Detectors and Instrumentation, SPIE, in press

The large submillimeter telescope (LST) is a proposed wide-field, 30m-class telescope operating from a ground-based site in the relatively unexplored 0.2 - 1mm waveband. The telescope will be equipped with imaging and spectroscopic instrumentation to allow astronomers to probe the earliest evolutionary stages of galaxies, stars and planets. It is intended to operate the telescope in the 200μm atmospheric window, giving access to unique science; probing the peak emission from the cosmic far-IR/submm background and proto-stellar cores. The wide field-of-view and superb image fidelity will be perfect for large-scale surveys of the sky, such as entire giant molecular clouds and of fields of dusty galaxies at early epochs. It will therefore be an ideal complement to new generation interferometers (such as ALMA). In this paper we present an update on the science case and outline initial designs for both the telescope and instrumentation.

Rapid and bright flaring activity was observed in the emission of 3C 2733 in early 1988. The behaviour of the source during the flare was reminiscent of the behaviour of classical Blazars, with rapid flux variations (several mJy night to night changes) and a high and variable polarization. Spectral slope changes are naturally explained in terms of synchrotron radiation and lead to a direct determination of the magnetic field in the flare emitting region. The value of the magnetic field is found to be ≈0.7G. Very rapid changes in the mm flux probably imply that the flare emitting plasma is moving at relativistic speeds towards us.

SCUBA-2, which replaces SCUBA (the Submillimeter Common User Bolometer Array) on the James Clerk Maxwell Telescope (JCMT) in 2006, is a large-format bolometer array for submillimeter astronomy. Unlike previous detectors which have used discrete bolometers, SCUBA-2 has two dc-coupled, monolithic, filled arrays with a total of ~10,000 bolometers. It will offer simultaneous imaging of a 50 sq-arcmin field of view at wavelengths of 850 and 450 microns. SCUBA-2 is expected to have a huge impact on the study of galaxy formation and evolution in the early Universe as well as star and planet formation in our own Galaxy. Mapping the sky to the same S/N up to 1000 times faster than SCUBA, it will also act as a pathfinder for the new submillimeter interferometers such as ALMA. SCUBA-2's absorber-coupled pixels use superconducting transition edge sensors operating at 120 mK for performance limited by the sky background photon noise. The monolithic silicon detector arrays are deep-etched by the Bosch process to isolate the pixels on silicon nitride membranes. Electrical connections are made through indium bump bonds to a SQUID time-domain multiplexer (MUX). We give an overview of the SCUBA-2 system and an update on its status, and describe some of the technological innovations that make this unique instrument possible., 16 pages, 14 figures, Invited talk at SPIE Glasgow 21-25 June 2004, Conference 5498

Spectral energy distribution (SED) analyses, that include new millimeter (mm) to far-infrared (FIR) observations, obtained with continuum instruments on the Nobeyama and James Clerk Maxwell Telescopes and Infrared Space Observatory (ISO), are presented for seven, nearby (< 45Mpc) FIR-bright elliptical galaxies. These are analyzed together with archival FIR and short-wave radio data obtained from the NASA/IPAC Extragalactic Database (NED). The radio to infrared SEDs are best fit by power-law plus greybody models of dust residing in the central galactic regions within 2.4kpc diameter and with temperatures between about 21 and 28K, emissivity index approximately 2, and masses from about 0.16 to 1.9 million solar masses. The emissivity index is consistent with dust constituting amorphous silicate and carbonaceous grains previously modeled for stellar-heated dust observed in the Galaxy and other nearby extragalactic sources. Using updated dust absorption coefficients for this type of dust, dust masses are estimated that are similar to those determined from earlier FIR data alone, even though the latter results implied hotter dust temperatures. Fluxes and masses that are consistent with the new FIR and submm data are estimated for dust cooler than 20K within the central galactic regions. Tighter physical constraints for such cold, diffuse dust (if it exists) with low surface brightness, will need sensitive FIR-submm observations with the Spitzer Space Telescope, SCUBA2, or ALMA., 22 pages, 9 figures, tentatively scheduled for the ApJ 10 September 2004, v612 issue

Images covering the central 450 by 100 arcsecond (about 8.0 by 2.0 kpc) of NGC 5128 (Centaurus A) obtained using SCUBA at 850 and 450 micron with beam sizes of 14.5 and 8 arcsecond respectively, are presented. These data are compared with those obtained at other wavelengths, in particular the optical, mid-infrared, and far-infrared continuum. The sensitive 850 and 450 micron images show that the submillimeter (submm) continuum morphology and spectral index distribution of Centaurus A comprise four regions: an unresolved AGN core, an inner jet interacting with gas in the dust lane, an inner disk of radius roughly 90 arcsecond, and colder outer dust. The inner disk has a high surface brightness, reverse-S-shaped feature in the 850 and 450 micron images that coincides with the regions of intense 7 and 15 micron continuum and a region of active star-formation. The infrared (IR) and submm images appear to reveal the same material as predicted by a geometric warped disk model consisting of tilted rings. We suggest this scenario is more plausible than that recently proposed in literature suggesting that the mid-IR emission in Centaurus A is primarily from a bar, with a structure that is different from the extended warped disk alone. A dust mass total of 2.2 million solar masses has been calculated within a radius of 225 arcsecond, 45% of which is in the star-forming region of radius about 90 arcsecond about the nucleus., 14 pages; 6 Gif (4 color) and 2 Postscript figures; Tentatively scheduled to appear in the v565 n1 ApJ January 20, 2002 issue

We present the results of new rest-frame far-IR observations of the z = 4.25 radio galaxy, 8C1435+635, which not only confirm that it contains an enormous quantity of dust (as first inferred from its mm-wave detection by Ivison 1995) but also allow the first meaningful constraints to be placed on the mass of this dust and associated gas. The new measurements consist of: (i) clear detections of sub-mm continuum emission at 450 and 850um obtained with the new sub-mm bolometer array, SCUBA, on the JCMT, (ii) continuum upper limits at 350, 750 and 175um obtained with SCUBA and the PHT far-IR camera aboard ISO, and (iii) a sensitive upper limit on the CO(4-3) line flux obtained with the IRAM 30-m MRT. The resulting rest-frame 33- to 238-um continuum coverage allows us to deduce that 2E8 Msun of dust at a temperature of 40 +/- 5 K is responsible for the observed mm/sub-mm emission. Using our CO upper limit, which constrains M(H2)/M(dust) to, 7 pages, 3 figures, LaTeX, uses emulateapj.sty (included), accepted for ApJ

Data resulting from multiwavelength observations the blazar QSO 3C 345 during a 2.5 magnitude optical outburst of were presented and discussed.

We present IRAS and submm data of the S1/IRS1 (Grasdalen et.al 1973, Harvey et.al 1979) region of the Rho Oph dark cloud. We have identified IRAS source 16235-2416 with IRS1. We announce the discovery of a new submm source, which is a cooler condensation of dust, and which we call SM1. It’s mass and density are such that it is a candidate protostar. We announce the first positive detection of grain mantles at such a low visual extinction in this cloud.

IYA2009 will be a great opportunity for all of us working in astronomy (and space) to make an impact; certainly locally and nationally and, we hope, globally. So what is going on and how can you participate? Ian Robson has the answers.

The magnitude and timescale of variations in the luminosity of quasars provide crucial constraints on the mechanism of emission and the physical size of the emitting region. We have observed variations by a factor of two in the infrared flux from the bright quasar 3C273 on a timescale as short as one day. Variations of this magnitude, over such short periods, are unprecedented. In February 1988, the behaviour of the source changed from having a stable infrared flux and slow optical variations (on timescales of weeks or months) to a state characterized by recurrent infrared and optical flaring. The optical variations were of several per cent per day, changing from increase to decrease approximately every week. The amplitude of the repeated optical flares was 30–40%. The data are consistent with re-injection/acceleration of electrons followed by rapid cooling. The inferred magnetic field is 0.7 gauss and the data are marginally consistent with no relativistic beaming.