The Knife Edge Galaxy Throws Astronomers For a Loop – Sky & Telescope


Double-looped Knife Edge GalaxyA 2008 symbol captured a 2nd loop across the Knife Edge Galaxy.D. Martínez-Delgado et al. / The Astrophysical Journal 2008

In 2006, a 20-inch newbie
telescope captured a picture of a watch-catching double loop of diffuse starlight
wrapping across the edge-on galaxy NGC 5907, some 50 million mild-years away
in Draco, the Dragon. However, two groups of astronomers now say the second one phase
of the double loop doesn’t exist.

The iconic symbol of
NGC 5907 (sometimes called the Knife Edge Galaxy or the Splinter Galaxy) was once got
through newbie astronomer R. Jay Gabany, the usage of the BlackBird Remote Observatory
(BBRO) in Cloudcroft, New Mexico. The effects have been described in 2008 in The
Astrophysical Journal through a workforce
led through David Martínez-Delgado (Max Planck Institute for Astronomy, Germany). In
addition to a identified diffuse elliptical characteristic first came upon in 1998 – maximum
most probably a tidally disrupted dwarf galaxy – Gabany’s symbol obviously presentations a 2nd

Then the radical Dragonfly telephoto array, which
excels at detecting low-floor-brightness options failed to look the second one
loop. (Read extra about Dragonfly in S&T’s
May 2019
factor.) “In reality, there’s only one [loop],” says Dragonfly’s
co-most important investigator Pieter van Dokkum (Yale University). Van Dokkum and
his colleagues printed their ends up in the October 2019 Astrophysical
Journal Letters.

Single-looped Knife Edge GalaxyWhen the Dragonfly telephoto array photographed the Knife Edge Galaxy, despite the fact that, they simply discovered a unmarried loop, the one who were identified since 1998. (Note that that is a composite symbol that mixes the Dragonfly symbol with a picture of the galaxy itself; the galaxy would in a different way saturate the delicate detectors.)
Van Dokkum et al. / Astrophysical Journal Letters 2019

Ignacio Trujillo (Institute
of Astrophysics of the Canaries, Spain), coauthor at the 2008 paper, was once no longer
inspired. He says that the Dragonfly workforce makes use of a nonstandard strategy to
quantify the intensity in their photographs. “They [do] no longer succeed in specifically deep low
floor brightness ranges,” he claims, a lot to the annoyance of van Dokkum.
Moreover, different devoted amateurs have additionally succeeded in photographing the
2nd loop, Trujillo provides.

But now, a workforce led through
Oliver Müller (University of Strasbourg, France) has seen the Knife Edge
Galaxy with the a lot higher 1.4-meter Milanković telescope in Serbia. They, too, fail to spot
indicators of the second one loop, as they write in Astronomy
& Astrophysics, however are wary of their observe: “The undeniable fact that now
two utterly impartial skilled groups have been not able to confirm the double
loop sheds some doubts on a minimum of one of the up to now discovered very low floor
brightness options,” they write.

Most recent photo of the Knife Edge GalaxyThe most up-to-date deep symbol of the Knife Edge Galaxy additionally presentations handiest a unmarried loop. O. Müller et al. / Astronomy & Astrophysics 2019

counters that a minimum of one of the Milanković photographs have been
taken when the galaxy was once at quite low elevation, hampering the detection
of extraordinarily diffuse options. “Their
knowledge can’t make clear this controversy and are nonetheless in line with
shallow photographs taken through tens of amateurs with very modest apparatus within the final
decade,” he says. But consistent with van Dokkum, “[Müller] put the nail within the
coffin of the Martínez-Delgado consequence.”

So what’s occurring? No
one is aware of. Unfortunately, the uncooked knowledge of the 2006 Gabany symbol was once misplaced in a
exhausting-force crash and can’t be reprocessed independently. Moreover, in accordance
to van Dokkum, a minimum of one of the affirmation photographs taken through different amateurs
have been processed the usage of Gabany’s printed symbol as a template. As Müller and his
co-authors write, there’s want for extra impartial observations that practice constant
scientific processing tactics.

Martínez-Delgado says extra observe-up observations through his workforce are in growth. “I´ll give a suitable answer [to the criticism] in a refereed publication soon,” he says. Adds Trujillo: “I am confident that the mystery will be finally solved later this year.” Meanwhile, when you occur to be a semi-skilled astro-imager, why no longer teach your software at the Knife Edge and give it a check out?


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