Distance is a tricky thing to measure in astronomy. We can’t use tape measures or rulers, and even more sophisticated methods like laser ranging are only good for the very nearest of neighbors, like the moon. That’s where distance indicators like Cepheids come in.
The El Gordo (in Spanish, “the fat one”), one of the most massive galaxy clusters observed, is an active merger of two large subclusters. Unraveling its dynamics provides insights into $latex \Lambda$CDM.
When two observations share some common information, they can be “cross-correlated” to extract it. In today’s example, we discover what the matter halos and energetic phenomena in the Universe have in common through a cross-correlation.
Thought dust could only bore you? Think again: it may obscure our view of time’s very beginning!
Our local “basin of attraction” is the region containing all the galaxies that would contract to a single point, if we were to neglect the dominant expansion. The authors define this region as our home supercluster, Laniakea.
The distribution of matter in the Universe has much to say about its constituents and evolution. Can the distribution of voids also help us understand the Universe?
Explore an astrophysical classic describing the effect of the Universe’s expansion on the seeds of galaxies.
What can the growth of structure in the Universe tell us about how regular matter and dark matter scatter? The authors develop a simple framework and get model-independent constraints; read on for the answer.
Different methods of measuring the Hubble constant yield slightly different values, but they are still in reasonable agreement.
Time delays in the light from AGNs’ dusty torii can tell us the intrinsic luminosity and hence the distance to the AGN.