Mid-IR images of methanol masers and ultracompact HII regions

Methanol masers and UCHII regions trace massive star formation sites. We have undertaken a mid-IR survey of 17 regions containing methanol masers and UCHIIs in order to locate the young stellar sources associated with them. The images were obtained from 8.7 to 18.8 μm with the mid-IR camera CID (Salas et al. 2003) on the 2.1m telescope of the Observatorio Astronomico Nacional at San Pedro Martir (Baja California, Mexico). The images were taken with a scale 0.55″/pix and the mean PSF was 1.5-2.0″(FWHM) close to the diffraction limit. We report as an example in Fig. 1 (left panel) our 18.8μm contours of IRAS 06061+2151 superimposed to the 2MASS Ks image. A young cluster of at least 4 sources has been found centered on the IRAS source (Anandarao et al. 2004). We have found two mid-IR sources coinciding with the source #2 and #4 of Anandarao et al. (2004). The source #4 is at the center of two H2 knots and a high velocity molecular outflow. The mid-IR emission from #2 is extended and coincides with the UCHII and MSX source. The methanol maser is approximately 10″ south of the source #2. The SEDs of both sources are illustrated in Fig. 1 (right panel). The IR spectral indices of source #2 and #4 are α(IR)=1.9 and 2.2 respectively.

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A blind survey of the 6.7 GHz methanol maser line

Symposium - International Astronomical Union ◽

10.1017/s0074180900222262 ◽

2002 ◽

Vol 206 ◽

pp. 143-146

Author(s):

Marian Szymczak ◽

Andrzej J. Kus ◽

Grzegorz Hrynek

Keyword(s):

Grid Point ◽

Hii Regions ◽

Triangular Grid ◽

Average Sensitivity ◽

Grid Pattern ◽

Methanol Maser ◽

Peak Flux ◽

Maser Line ◽

Methanol Masers ◽

Ultracompact Hii

A blind survey for 6.7GHz methanol maser emission has been made with the 32 m Toruń radio telescope. The survey consists of 4,800 spectra on an equilateral triangular grid pattern with each grid point separated by 4.4 covering a field of ∼21 deg2 at galactic longitudes 20° to 40° and galactic latitudes ±0°52. The average sensitivity was 1.6 Jy and the spectral resolution was 0.04kms−1. A total of 99 sources were detected, 28 of which were not found during previous searches of IRAS-selected ultracompact HII regions. The peak flux density of new detections is usually lower than 30 Jy. About half of the methanol masers have no IRAS counterparts within a radius of 2. The nature of these sources is unclear.

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A Remarkable Bipolar Flow in the Center of the Rho Ophiuchi Cloud

International Astronomical Union Colloquium ◽

10.1017/s0252921100023885 ◽

1989 ◽

Vol 120 ◽

pp. 300-300

Author(s):

Ph. Andre ◽

J. Martin-Pintado ◽

D. Despois ◽

T. Montmerle

Keyword(s):

Mass Loss Rate ◽

Extreme Case ◽

Width Ratio ◽

Dark Cloud ◽

Molecular Outflow ◽

Ir Sources ◽

Near Ir ◽

Exciting Source ◽

Rho Ophiuchi ◽

Cloud Core

Using the IRAM 30-m telescope in August and December 1988, we have discovered the first molecular outflow in the central part (L1688) of the nearby ρ Ophiuchi dark cloud. This outflow, found in the J = 2 — 1 line of 12CO near the cloud core A, is an extreme case, weak (outflow mass-loss rate ≈ 5 x 10−8M⊙yr−1) and highly collimated (lenght to width ratio > 14), which explains why it has escaped previous detections with smaller telescopes. The high-velocity molecular gas is hot and optically thin, making the J = 2 — 1 line of 12CO ≈ 3-4 times stronger than the J = 1 — 0 line. Unexpectedly, this outflow does not appears to be driven by any of the embedded near-IR sources known in this region previous deep VLA surveys of the cloud (André, Montmerle, and Feigelson, 1987; Stine et al., 1988; André et al., in prep.). The outflow exciting source is thus probably a very low-luminosity ((L < 0.1L⊙) young stellar object. Using the 30-m equipped with the MPIfIR bolometer, we have very recently found (March 1989) that this object is the strongest continuum point source of L1688 at 1.3 mm. By analogy with L1551-IRS5 and HL Tau, the radio properties of this source suggest that it possesses a weak, possibly collimated, ionized wind and a relatively massive, cold circumstellar disk (Mdisk ≈0.1M⊙).

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IRAS Observations of Collisionally Heated Dust in Large Magellanic Cloud Supernova Remnants

International Astronomical Union Colloquium ◽

10.1017/s0252921100102696 ◽

1988 ◽

Vol 101 ◽

pp. 383-386

Author(s):

James R. Graham ◽

A. Evans ◽

J.S. Albinson ◽

M.F. Bode ◽

W.P.S. Meikle

Keyword(s):

Interstellar Medium ◽

Supernova Remnants ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Substantial Fraction ◽

X Ray ◽

Ir Sources ◽

Atomic Cooling ◽

Dust Grain ◽

Ir Emission

AbstractIRAS additional observations show that luminous (104−105 L⊙) far-IR sources are associated with the Large Magellanic Cloud (LMC) supernova remnants N63A, N49, N49B, and N186D. Comparison of the IRAS and X-ray data shows that a substantial fraction of the IR emission from three of the SNRs can be accounted for by collisionally heated dust. The ratio of dust-grain cooling to total atomic cooling is ~10 in X-ray emitting gas (T~106 K). We show why dust cooling does not dominate, but probably speeds SNR evolution in an inhomogeneous interstellar medium.

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Effects of self-consistent rest-ultraviolet colours in semi-empirical galaxy formation models

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2586 ◽

2020 ◽

Vol 498 (2) ◽

pp. 2645-2661 ◽

Cited By ~ 2

Author(s):

Jordan Mirocha ◽

Charlotte Mason ◽

Daniel P Stark

Keyword(s):

Galaxy Formation ◽

Surface Density ◽

Empirical Relationships ◽

James Webb Space Telescope ◽

Luminosity Functions ◽

Self Consistent ◽

The Mean ◽

Semi Empirical ◽

Ir Emission ◽

Dust Surface

ABSTRACT Connecting the observed rest-ultraviolet (UV) luminosities of high-z galaxies to their intrinsic luminosities (and thus star formation rates, SFRs) requires correcting for the presence of dust. We bypass a common dust-correction approach that uses empirical relationships between infrared (IR) emission and UV colours, and instead augment a semi-empirical model for galaxy formation with a simple – but self-consistent – dust model and use it to jointly fit high-z rest-UV luminosity functions (LFs) and colour–magnitude relations (MUV–β). In doing so, we find that UV colours evolve with redshift (at fixed UV magnitude), as suggested by observations, even in cases without underlying evolution in dust production, destruction, absorption, or geometry. The observed evolution in our model arises due to the reduction in the mean stellar age and rise in specific SFRs with increasing z. The UV extinction, AUV, evolves similarly with redshift, though we find a systematically shallower relation between AUV and MUV than that predicted by IRX–β relationships derived from z ∼ 3 galaxy samples. Finally, assuming that high $1600\hbox{-}{\mathring{\rm A}}$ transmission (≳0.6) is a reliable Ly α emitter (LAE) indicator, modest scatter in the effective dust surface density of galaxies can explain the evolution both in MUV–β and LAE fractions. These predictions are readily testable by deep surveys with the James Webb Space Telescope.

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Far IR Emission and Thermal Properties of Ceramics Coated Fabrics by IR Thermography

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.321-323.849 ◽

2006 ◽

Vol 321-323 ◽

pp. 849-852 ◽

Cited By ~ 13

Author(s):

Chung Hee Park ◽

Myoung Hee Shim ◽

Huen Sup Shim

Keyword(s):

Far Infrared ◽

The Body ◽

Thermal Manikin ◽

Evaporative Resistance ◽

Clothing Insulation ◽

Ir Camera ◽

Warm Up ◽

Coated Fabrics ◽

Ir Emission ◽

Body Heat

The purpose of this study was to develop the warm-up suit that is comfortable as well as has good thermal performance. The function of warm-up suit is to keep the body warm and thus to lose it’s weight by sweating. Ceramic powders, such as zirconium and magnesium oxide have been incorporated into the textile structures to utilize the far infrared radiation effect of ceramics, which heat substrates homogeneously by activating molecular motion. Thermal manikin tests were conducted to determine the clothing insulation and evaporative resistance of the selected warm-up suits. Also, the far IR emission effects of ceramics containing laminate on the body heat transfer were evaluated with the thermogram data using IR camera. The results showed that the ceramics inside laminate slightly increased the thermal insulation and the evaporative resistance. Thermogram showed that when the fabric was heated with the thermal manikin, surface mean temperatures of fabrics were increased as the ceramic incorporated, and the heat storage performance was confirmed.

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Pan–Tilt IR Scanning Method for the Remote Measurement of Mean Radiant Temperatures at Multi-Location in Buildings

Remote Sensing ◽

10.3390/rs13112158 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2158

Author(s):

Dong-Seok Lee ◽

Jae-Hun Jo

Keyword(s):

Thermal Comfort ◽

Thermal Environment ◽

Radiant Heat ◽

Cooling Systems ◽

Ir Camera ◽

Scanning Method ◽

Image Frame ◽

Heating And Cooling ◽

The Mean ◽

Time Evaluation

The mean radiant temperature (MRT) is an indicator for evaluating the radiant heat environment near occupants and is determined by the radiant heat exchange between the occupants and their surroundings. To control various heating and cooling systems according to the occupants’ thermal comfort, it is essential to consider MRTs in the real-time evaluation of thermal environment. This study proposes a pan–tilt infrared (IR) scanning method to estimate the MRTs at multiple occupant locations in real buildings. The angle factor was calculated by defining the specific classification criteria for dividing the entire indoor surface into sub-surfaces. The coupling IR camera and pan–tilt motor were applied to enable storing data pairs of IR thermal image frame (IR image frame) and pan–tilt angle so each surface area taken by the IR camera can have its direction information. The measurement method of the mean surface temperature using the pan–tilt IR system was presented. The pan–tilt IR system hardware and MRT monitoring software were developed. An experiment was performed to verify the applicability of the proposed pan–tilt IR scanning method. By comparing the surface temperatures measured using a contact thermometer and the proposed IR system, the contact thermometer could cause inaccurate measurement of surfaces with a non-uniform distribution of temperature. The difference between surface temperatures increased by up to 15 °C and, accordingly, the MRT distributions differed by up to 6 °C within the same space. The proposed IR scanning method showed good applicability in various aspects. This paper reports that the MRT has a significant effect on the occupants’ thermal comfort and also suggests considering MRTs in the real-time evaluation of thermal environment to control various heating and cooling systems appropriately.

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The Millennium Galaxy Catalogue: the severe attenuation of bulge flux by dusty spiral discs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308018231 ◽

2007 ◽

Vol 3 (S245) ◽

pp. 403-406

Author(s):

Simon P. Driver ◽

Keyword(s):

Close Agreement ◽

Luminosity Functions ◽

Central Regions ◽

The Mean ◽

Galaxy Population ◽

Ir Emission ◽

Optical Appearance

AbstractUsing the Millennium Galaxy Catalogue we quantify the dependency of the disc and bulge luminosity functions on galaxy inclination. Using a contemporary dust model we show that our results are consistent with galaxy discs being optically thick in their central regions ($\tau_B^f=3.8\pm0.7$). As a consequence the measured B-band fluxes of bulges can be severely attenuated by 50% to 95% depending on disc inclination. We argue that a galaxy's optical appearance can be radically transformed by simply removing the dust, e.g. during cluster infall, with mid-type galaxies becoming earlier, redder, and more luminous. Finally we derive the mean photon escape fraction from the integrated galaxy population over the 0.1 μm to 2.1 μm range, and use this to show that the energy of starlight absorbed by dust (in our model) is in close agreement with the total far-IR emission.

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Mid-Infrared Observations of the Galactic Center Arc and the Sgr A East HII Region

Symposium - International Astronomical Union ◽

10.1017/s0074180900186644 ◽

1989 ◽

Vol 136 ◽

pp. 287-292 ◽

Cited By ~ 1

Author(s):

F. Yusef-Zadeh ◽

C. M. Telesco ◽

R. Decher

Keyword(s):

Galactic Center ◽

Hii Regions ◽

Radio Continuum ◽

Radio Flux ◽

Ir Camera ◽

Hii Region ◽

Sgr A ◽

5 Ghz ◽

Almost All ◽

Ir Emission

We have used the 20-pixel IR camera to observe thermal IR emission from dust associated with the radio continuum Arc near the Galactic center and the cluster of HII regions in the immediate vicinity of Sgr A East. We detected strong 10μm emission from the eastern and western arched filaments (G0.1+0.08), from an unusual pistol-shaped structure known as G0.15–0.05 and from the brightest member of the Sgr A East HII region. Spatial maps of these features at 10μm with a resolution of 4.1″ × 4.2″ are presented and are compared with 5-GHz radio images. We find a general spatial correlation between the ionized gas and the dust distributions. The ratio of IR to radio flux densities is significantly different in the eastern and western arched filaments, which suggests that the source of heating has a softer spectrum along the eastern arched filaments. In addition, the ratio of IR to radio flux densities, which is typically ~10 in normal Galactic HII regions excited by O stars, is at least a factor of two higher than this value in almost all the sources we have observed. This suggests that additional mechanisms other than trapped Lymanαradiation should be present in heating the dust, e.g. stochastic heating of small dust grains by energetic particles associated with the nonthermal filaments.

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The Source Populations Producing the Cosmic IR Background

Symposium - International Astronomical Union ◽

10.1017/s0074180900226181 ◽

2001 ◽

Vol 204 ◽

pp. 283-299

Author(s):

Alberto Franceschini

Keyword(s):

Energy Content ◽

Infrared Space Observatory ◽

Massive Galaxies ◽

Ir Sources ◽

Stellar Formation ◽

Evolutionary Scheme ◽

Multi Wavelength ◽

Transient Events ◽

Source Populations ◽

Ir Emission

Deep surveys performed with millimetric telescopes and with the Infrared Space Observatory have partly resolved the Cosmic IR Background (CIRB) into a population of IR sources characterized by extremely high rates of cosmological evolution (comparable to or higher than those observed for quasars). We report in this paper on early attempts to study these sources and to understand their physics. The IR multi-wavelength galaxy statistics can be explained by assuming, for the bulk of the IR population, spectra typical of starbursts, an indication that stellar more than quasar activity produces the IR emission by faint galaxies. From our fits to the observed optical-IR SEDs, the latter appear to mostly include massive galaxies hosting violent starbursts (SFR ~ 100 M⊙/yr). We interpret the strong redshift-evolution as an increase with z of the rate of interactions between galaxies (density evolution) and an increase of their IR luminosity due to the more abundant fuel available in the past (luminosity evolution). Our evolutionary scheme considers a bimodal star formation (SF) in galaxies, including long-lived quiescent SF, and enhanced SF taking place during transient events triggered by interactions and merging. The large energy content in the CIRB may possibly require a top-heavy stellar IMF associated with the starburst phase. The observed evolution of galaxy IR emissivity is so strong from z=0 to z ~ 1 that the CIRB spectral shape imposes a fast turnover to the evolution at z > 1: scenarios in which a relevant fraction of stellar formation occurs at very high-z (e.g., the bulk of stars in spheroids) are not supported by our analysis.

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