I can comprehend gravitational waves and the crazy precision needed to measure them, but I’ve still never been able to understand how they determine the objects that merge to cause the waves.
I see articles about having detected things like “two supermassive black holes”, “a supermassive black hole and a neutron star”, or “one massive black hole and an abnormally large poodle” colliding. I have no idea how they feel they have any real knowledge of what objects at what sizes led to the waves from simply being able to see the relative size of the waves and now long they last.
I believe most of the time they run models with the known parameters and use that to decide what the objects were. It also seems that we appear to understand what different wave patterns look like and know what the source objects tend to be. Other times I believe they can figure out what one object was but not the other and just kinda have to guess at it. I would also suspect that once they determine the location in the sky where the event happened they can check and see if there are any past observations of that area of the sky by other telescopes and just look and see what was there previously.
I’m sure I’m greatly simplifying this, but that’s what I turned up with a bit of reading on the LIGO website for Gravitational Wave Sources and Types.
With the interferometers they can estimate the mass of the 2 objects entering in collision and the resulting one.
Since there are multiple interferometers, they can also point to the region of the sky it happens. The “alert” can be picked up by other observatories which can look there on all frequencies.
Depending on if there is an explosion or not they can confirm if the objects were neutron stars or black hole (the details are a bit fuzzy on my head for the black hole / neutron star merger).
I can comprehend gravitational waves and the crazy precision needed to measure them, but I’ve still never been able to understand how they determine the objects that merge to cause the waves.
I see articles about having detected things like “two supermassive black holes”, “a supermassive black hole and a neutron star”, or “one massive black hole and an abnormally large poodle” colliding. I have no idea how they feel they have any real knowledge of what objects at what sizes led to the waves from simply being able to see the relative size of the waves and now long they last.
I believe most of the time they run models with the known parameters and use that to decide what the objects were. It also seems that we appear to understand what different wave patterns look like and know what the source objects tend to be. Other times I believe they can figure out what one object was but not the other and just kinda have to guess at it. I would also suspect that once they determine the location in the sky where the event happened they can check and see if there are any past observations of that area of the sky by other telescopes and just look and see what was there previously.
I’m sure I’m greatly simplifying this, but that’s what I turned up with a bit of reading on the LIGO website for Gravitational Wave Sources and Types.
Edit: typos
With the interferometers they can estimate the mass of the 2 objects entering in collision and the resulting one.
Since there are multiple interferometers, they can also point to the region of the sky it happens. The “alert” can be picked up by other observatories which can look there on all frequencies.
Depending on if there is an explosion or not they can confirm if the objects were neutron stars or black hole (the details are a bit fuzzy on my head for the black hole / neutron star merger).