NGC 7331 from HST, Ehsan Ebrahimian

NGC 7331 from HST

NGC 7331 from HST, Ehsan Ebrahimian

NGC 7331 from HST

Equipment

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Acquisition details

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Description

The data was taken during August 2015 with Wide Field Camera 3 Instrument, using ultraviolet (UVIS F275W), visible ( UVIS F438W ) and infrared ( UVIS F814W) wideband filters. The data files are:

hst_14202_01_wfc3_uvis_f275w_sci.fits

hst_14202_01_wfc3_uvis_f438w_sci.fits

hst_14202_01_wfc3_uvis_f814w_sci.fits

I displayed ultraviolet light in blue, visible light in green, and infrared in red, so the blue color is associated with the young hot stellar population. The core also has a red color from old stars, and there is a supermassive black hole at the center.

The most challenging data were ultraviolet data which had a low signal-to-noise ratio. So I used noise filtering algorithms (wavelet noise filtering and non-linear filters) to obtain cleaner ultraviolet data. I also sharpened the details of the red and green lights by deconvolution (using the van Cittert algorithm).

I used MATLAB to have better control over the data and enjoy the maths behind it. There is only brightness and contrast adjustment at the end with photoshop.

Comments

Histogram

NGC 7331 from HST, Ehsan Ebrahimian