Clear skies were predicted for Sonoma County (north of Santa Rosa)
on Saturday night, April 15th, so I headed to Lake Sonoma, near Geyserville,
and met a half-dozen other Bay Area observers. The forecast called
for above average transparency, though the seeing was expected to
be below average or poor. Instead of lugging my 24” Starstructure
for one night, I decided to take my smaller scope - a 14.5” f/4.3
Starmaster (Zambuto optics), which made set up a snap and permitted
using an adjustable observing chair over much of the sky.
It turned out the skies were crystal clear, except for one band of
clouds that slowly passed through to the south, with above average
darkness for this site (SQM readings of 21.4-21.5). We were surprised
that the seeing turned out much better than expected, with pinpoint
images at moderately high power. The one downside was a steady breeze
that persisted through the night, enough to be an annoyance at times
with a few loose charts flying off my table that I had to chase down.
I took notes on 30 galaxies, so the ones below are just a small sample
— but all follow the super theme. I returned to observe at the
same site two nights later (Monday, April 17th) and will post a separate
report.
Steve Gottlieb
As far as the super-night, one highlight was IC 3322A = UGC 7513 (12
25 42.9, +07 12 58), a fairly dim super-thin edge-on, a little over
a degree southwest of M49 in the Virgo cluster and 20’ ESE of
the giant elliptical NGC 4365. The galaxy was stretched 10:1 NNW-SSE,
roughly 2.0’x0.2’ — just a low surface brightness streak
with no distinct core or nucleus.
But planted on its north tip was the “prominent” 13th magnitude
Supernova! This Type Ia was discovered on March 30th at the Zwicky Transient
Facility (ZTF) at Palomar, with a camera that captures a 47 square degree
field and images 3750 sq. degrees per hour. The supernova, designated
SN 2021hiz, is likely near maximum brightness as it dominated the glow
of the edge-on galaxy!
Next was NGC 5018, a bright elliptical in southern Virgo (13 11 45.7,
-19 15 42). The galaxy was logged as "bright, fairly large, slightly
elongated, ~1.8'x1.5', very strong and sharp concentration with a small,
very bright core and an intense nucleus. A mag 14.6 star was seen just
outside the halo.” NGC 5018 appears to be a post-merger as a deep
image from the VLT Survey Telescope in the Atacama Desert reveals outer
shells and star streams — likely the remains of a cannibalized
galaxy. Just 7’ ESE is NGC 5022, which I recorded as "fairly
faint, very thin edge-on ~6:1 SSW-NNE, ~1.5'x0.25'. A mag 11.1 star
is ~2 N. "
The real target, though, was another Type Ia supernova, SN 2021fxy,
discovered nearly a month ago by Koichi Itagaki, a prolific supernova
hunter from Japan with scores of discoveries to his name. It was seen
as a mag 14.2 "star", just 20" N of center of the galaxy,
close to the edge of the core and within the halo. A similar mag 14.1
star was noted 2' N of the galaxy.
UGC 9242 is a super-flat galaxy in Bootes (14 25 21.3, +39 32 18) —
in fact, one of the narrowest known, with dimensions 5.0’x0.25’
(nearly 20:1 axial ratio). Here’s an excellent image from the late
Rick Johnson, who often posted on CloudyNights. I’ve observed this
galaxy several times before (including through Jimi Lowrey’s 48”),
but this view was using Bob Douglas’ 18” Starmaster. It was
an extremely faint sliver at least 2' in length. A mag 13 star is less
than 1' S of the ENE tip and helps to pinpoint the position of the dim
streak.
Although not quite as flat as the last galaxy, UGC 5459 in Ursa Major
(10 08 10.3, +53 04 59) still qualifies as a super-thin (nearly bulge-less
edge-on). It’s brighter than UGC 9242, but is nearly hiding behind
a mag 8.7 star! At 158x, it wasn’t difficult — a nice streak
extending ~2’x0.25’, seeming to shoot out from the star. The
galaxy has a low surface brightness, though, with only a weak brightening
towards the center. The superimposed star (HD 87704) is one of 4 bright
stars in the field forming a very distinctive rhombus shape.
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