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Published byRosalyn Willis Modified over 9 years ago
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Matthew.Smith@astro.cf.ac.uk
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Last Version: DR3.5 Released June 2012 Pipeline: Optimised De- glitcher BriGAdE Allow Dark Pixel drift removal Manual Jump and glitch-tail removal New Pixel sizes: 6, 8, 12 "
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V1 V2 V3 V4 Latest Version: DR4 Released June 2012 Updates from DR3.5 to DR4: PMW cal factor v5 to v8 applied to map (1.0067) Second-order deglitching Relative Gain Corrections for extended emission
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For extra-galactic science we have optimum SPIRE pipeline (cirrus scale structures may- not be optimal) Pointing Products Star-Tracker Temperatures were changed on OD 320 to prevent hot-pixel issues Herschel updated on OD 761 to account for changes New pointing products OD 320-761 available (~ 2")
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Planned Updates on DR4 NEW CALIBRATION! (point + ext) New Pointing Product Updates not going to be applied Planck Zero Level Calibration De-striper (except on a set of cirrus maps for Simone
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New Neptune measurements by George Increase of ∼3%, ∼2% & ∼1% at 250, 350 and 500µm Aperture Efficiency values now included (fairly small) Long term – will be new updates on the assumed Neptune and Uranus models
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Chris North, Matt Griffin, & co Applies to fully extended until >100' Working on adaptive script for intermediate sources 10 – 100'. Will require TWO versions of SPIRE for point/extended or even individual object maps that are optimised to their size
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Old Philosophy – FUDGE IT: Modify the filter curve with a λ 2 weighting Wrong for 2 reasons: 1: Beam solid angle varies as λ 1.7 2: Not a single value of beam area appropriate for sources Depending on your source spectral index could correct the wrong way.
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Why the difference? See white board! New Philosophy As well as apply colour–corrections account for varying beam area across band Talking somewhere in the region 0-10% change in values New pipeline surface brightness product in MJy/sr Is a Planck zero level corrected map as well (but not really worth it)
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An original aim of the HRS (and many other surveys) to find cold dust in outskirts of galaxies. Dust could be driven out or formed outside disk. Has been detected by quasar absorption (Menard et al. 2010) – see next slide. Not been possible to detect emission before as dust is cold and very low surface brightness. Still work in progress...
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Potential Questions? How far can we detect dust emission What are the properties of the dust at these wavelengths Extreme environment for SF etc… Only used SPIRE only due to sensitivity / reduction method / areas covered Still work in progress
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uses SDSS ∼85,000 quasars at z > 1 Correlated with 24 million galaxies at z∼0.3 Find reddening and magnification Half of dust is outside galaxies
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HRS object Criteria: Late-type galaxies Indentified as detection Extended Source No other bright contaminating object No heavy cirrus contamination Inclination < 60°
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Restricted to galaxies with D25 > 3ˊ
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Have randomly chosen 32 galaxies (1/4 sample) and repeated procedure Measured where it crosses a fixed threshold (equivalent to 1.8R 25 ) Repeated 40,000 times Results do not vary by a large amount (±0.15 R 25 )
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Probably Not! Nearby Objects Large extended objects Bright Maps not large enough Wide Field Surveys, e.g., H-ATLAS Many objects so can be sensitive Large areas so can reach high scales Angular size is smaller, flux of central beam dominates at radii < 2.0R 25
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Minimise χ 2 model by: Trial Model Convolving it with beam Calculate χ 2 Following Schruba et al. 2011 do not fit centre 30˝ Need 2 exponentials
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The fraction of dust emission between 1-2 R 25 is 6.6, 8.0 and 10.6% for the 250, 350 and 500µm band. If integrate the broken-exponential model from 0⇢∞ find that 4.2% of emission at 250µm Rough agreement with 15kpc Medard value but I need to redo this.
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Work in Progress… All images smoothed and re-gridded to PLW images Temperature stabilises around 16K Means a higher fraction of dust mass outside R25 than fraction 250µm emission
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Difference is less prounonced as Cortese 2010 Individual objects are in agreement Highly HI def are significantly different from HI def < 0.0 (Mann-Whitney U statistic)
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Not yet Investigated…
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Are low mass galaxies cosmic hoovers picking up dust expelled from high stellar mass galaxies?
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Schruba et al. with CO with HERACLES reach 1.0-1.2R25 HI Paolo Serra suggested a thesis by Thomas Martinsson Unknown for other wavelengths (e.g., UV)?
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