Astronomical source extraction in non uniform background

In summary, the speaker is having difficulty extracting astronomical sources from Herschel images due to a highly non-uniform image background. They have tried using source extractor in HIPE but are unsure of its reliability. They ask for recommendations for software or methods to deal with this issue. Another individual suggests using the getsources program, specifically designed for Herschel data, which can separate compact sources from the irregular background. However, if the background has structures similar to the sources, there may not be a solution available. Questions are also asked about the type of sources and Herschel instruments being used.
  • #1
sonutabitha
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I have been working with some Herschel images and I am finding it difficult to extract the astronomical sources from the image. The image background is extremely non uniform so i am not able to differentiate between the background and the source. I used some tasks in HIPE like source extractor but am sceptical about it's reliability as it assumes the background to be uniform. Is there any software to deal with my problem? Is there any way out?
Kindly help
 
  • #3
My background is particle physics, not astronomy, but looking for structures in nonuniform background is a typical problem in particle physics as well.

Do you have some model to describe the nonuniform background? Non uniform in which way?
There are various fitting tools that look for peaks above a (relatively) smooth background.
If the background has structures that look the same as the actual sources and no theoretical description for them, then I don't see hope.
 
  • #4
What kind of sources are you attempting to extract? What Herschel instruments are you using?

If you are looking at star forming regions then getsources is the way to go for sure. It is a bit involved to get it going but it works like a dream. Since star forming regions always have emission on multiple size scales the algorithm focuses on separating compact sources from the irregular background with iterative convolutions. Even if you aren't working with maps of star forming regions give it a try. It's built for Herschel so it plays nice with the all the PACS and SPIRE wavebands.

http://www.herschel.fr/cea/gouldbelt/en/getsources/

If you aren't looking to get involved with a more complicated algorithm then you may have some trouble depending on what exactly you are observing.
 
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1. What is astronomical source extraction in non-uniform background?

Astronomical source extraction in non-uniform background is the process of identifying and measuring the intensity and position of celestial objects, such as stars or galaxies, in images that have a non-uniform or varying background. This is a common challenge in astronomy, as many images taken by telescopes have variations in background due to atmospheric conditions or instrument noise.

2. What are the techniques used for astronomical source extraction in non-uniform background?

Some common techniques used for astronomical source extraction in non-uniform background include background subtraction, thresholding, and aperture photometry. Background subtraction involves removing the varying background signal from the image, while thresholding involves setting a threshold for object detection. Aperture photometry measures the total flux of an object by summing the pixel values within a defined aperture.

3. What are the challenges in astronomical source extraction in non-uniform background?

One of the main challenges in astronomical source extraction in non-uniform background is accurately separating the signal from the background. This can be difficult, as the background signal can vary in both spatial and temporal scales. Additionally, the presence of noise in the image can also make it challenging to identify and measure faint objects.

4. How is astronomical source extraction in non-uniform background used in research?

Astronomical source extraction in non-uniform background is used in a variety of research areas, including studying galaxy evolution, identifying and characterizing new objects, and measuring the properties of astronomical sources, such as their brightness and position. This technique is essential for processing and analyzing large datasets from telescopes and spacecraft.

5. Are there any tools or software available for astronomical source extraction in non-uniform background?

Yes, there are many tools and software available for astronomical source extraction in non-uniform background, such as SExtractor, DAOPHOT, and IRAF. These tools often have various algorithms and customizable parameters for users to optimize their source extraction process. Some tools are also specifically designed for extracting sources in specific types of images, such as infrared or X-ray images.

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