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You might have heard about the LISA mission, an upcoming space-based gravitational-wave detector. It's often described as @LIGO in space. But look closely, and there are many interesting differences b/w them. One diff is the way GWs interact with them. A thread about that 
@LISACommunity is a triad of satellites separated by 2.5 million km shooting laser beams at each other. Scheduled to launch in the 2030s, the long arm lengths allow us to detect gravitational-waves with lower frequencies than @LIGO- @ego_virgo. It's going to be totally awesome!!
Now the way a GW interacts with the detector is determined by its antenna patterns. Think of them roughly as multiplicative factors between the GWs and the signal we see in the detector. In general, these factors depend on the frequency and sky position of the GW signal.
The image shows the antenna patterns of a LIGO-like detector (for the + polarization, not very imp here) for a GW coming directly from above. The horizontal axis is the frequency of the wave. Notice how the antenna patterns don't change with frequency until about 2000 Hz or so.
The image shows the noise of the LIGO Livingston detector [1] and all known noise sources. The lower these curves, the better we can detect GWs. Notice how the blue curve forms a "bucket" b/w ~20 Hz - 1000 Hz where LIGO is most sensitive. Beyond this bucket, noise dominates.
![The image shows the noise of the LIGO Livingston detector [1] and all known noise sources. The lower these curves, the better we can detect GWs. Notice how the blue curve forms a "bucket" b/w ~20 Hz - 1000 Hz where LIGO is most sensitive. Beyond this bucket, noise dominates.](https://pbs.twimg.com/media/EtaknL0XEAQBecl.jpg "The image shows the noise of the LIGO Livingston detector [1] and all known noise sources. The lower these curves, the better we can detect GWs. Notice how the blue curve forms a \"bucket\" b/w ~20 Hz - 1000 Hz where LIGO is most sensitive. Beyond this bucket, noise dominates.")
But the LIGO antenna patterns are essentially constant in the 20 Hz-1000 Hz bucket. We say LIGO & Virgo work in the large-wavelength limit where the GW wavelength is much larger than the detector's size and the GW frequency does not affect how it interacts with the detector.
The case is entirely different for LISA. LIGO operates in the millihertz (10^-3) frequency band, and here LISA's antenna patterns change a lot with frequency. When looking at LISA data, we have to account for this, unlike in LIGO! But, look at what's happening above 0.02 Hz ...
.. The antenna patterns oscillate around a value of zero. Remember that they are multiplicative factors b/w the actual GWs and the signal in the detector. When they are close to zero, the detector will have no ability to detect GWs. Essentially LISA can't detect any GWs above ...
... 0.03 Hz, and in this range, LISA operates in the small wavelength limit, the opposite of LIGO. But this limitation is not due to noise in the instrument. Rather the sensitivity of LISA is limited at frequencies above 0.03 Hz by the physics of GWs itself!
[1] noise budget plot taken from https://arxiv.org/abs/2008.01301
