Arp 119 / UGC 849 / Mrk 984
| Designation(s) | Arp 119, UGC 849, Mrk 984 |
| Object Type(s) | Galaxy |
| Relevant Catalog(s) | All (Chron), Arp |
| Arp Category | Elliptical galaxies close to and perturbing spiral galaxies |
| Obs. Lat/Long | 42° 17', 073° 57' |
| Constellation | Pisces |
| Date and Time Observed | 2025-09-21 23:02:00 |
| Instrument | EdgeHD 8" w/f7 reducer-1,422mm FL |
| Camera | Player One Apollo-M Mini |
| Image Details | Up is 180.1 degrees E of N. Transparency: Fair. Seeing: Good. Total integration time was 1 hour. Exposures 15s@300g, No Filter. Dithered and recentered in SharpCap. No guiding. |
| Description | Arp saw an Elliptical Galaxy perturbing a nearby Spiral. His notes say, cryptically, "Some material seems attracted, some repelled," which is a prescient comment, given more modern research. The "deepest dive" I found was published by Hearn & Lamb (THE ASTROPHYSICAL JOURNAL, 551:651È670, 2001 April 20). They concluded: "The morphology of both members can be fitted well by a simulation in which a gas-rich disk galaxy has been impacted by an equal-mass elliptical that had a trajectory approximately perpendicular to the plane of the disk and passed through the disk slightly off-center", creating the density wave seen in the "peculiar" spiral, both because of direct disturbance and because it triggered accelerated star formation. "We deduce that the star formation rate in this density wave was not a smooth function of time but that, so far, three major episodes of star formation have occurred at roughly 25-30 million year intervals." The gallery contains an illustration which shows a computer simulation duplcating evolution of the "fan shaped" perturbation. |
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