Category Archives: galaxies

astroimaging, astronomy, galaxies, open clusters

Forty Globs in One

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Can you image 40 globular clusters at one time? Well – yes! In fact, with a wide enough field of view you can image many more, especially if you point towards such a rich collection like those found in the Andromeda Galaxy. I’d previously done so using my WO refractor, but this time wanted to go much closer in, staring at the large open cluster NGC206, located in the outer arms of M31.

NGC206, located in the Andromeda Galaxy (Luminance only)Here is an image taken through the Newtonian at 1583mm focal length which shows the region around NGC206 (in L channel only). 

The annotated image below clearly shows the location of forty globular clusters from the Bologna Catalogue (plotted using Pixinsight’s Annotate tool, importing a custom catalogue generated as an extract from the Vizier tool). Figures in brackets are the catalogue magnitude. 

NGC206, located in the Andromeda Galaxy - annotated imageTime escaped me in doing the colour for this image, so it will remain as a greyscale image for the time being. However, the mottled effect in the star clouds within M31 are in fact real – close examination of the mottling and comparison to archive DSS images reveal identical patterns in the clouds – it’s at this level we start to resolve smaller stars in the Andromeda Galaxy – even larger telescopes such as the Subaru or the Hubble Space Telescope reveal much more detail in the star clouds.

Image captured Oct/Nov 2018 from W Oxfordshire, UK.

astroimaging, astronomy, galaxies

M96 in Leo: An Imperfect Spiral Galaxy

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M96 - Spiral in Leo

Messier 96 is an imperfect, intermediate spiral galaxy in the constellation of Leo, at a distance of approximately 30 million light years. It is a highly asymmetric galaxy – the gas and dust is not evenly spread through its spiral arms, and the core doesn’t appear to be exactly at the galaxy’s centre. This is thought to have arisen due to interactions with other nearby galaxies (eg M95 which is about 40′ to the west of M96 from our viewpoint).

The spiral arms show bright knots of young hot stars (more easily visible in colour images) indicating recent starbirth, and visible through the outer dusty reaches are many background galaxies including the edge on galaxy 2MFGC 8391 shown here to the lower right (north-east) of the centre of M96. 

Also in this image is my current distance record (though not something I’ve tried to push!) – QSO J104619.26+115223.4 is present (and annotated in the image shown) – this quasar has a measured redshift of z=2.83, placing it at a distance of of 11.4 billion light years (light travel time) in our current best estimates of the universe’s parameters. This quasar shines dimly at a magnitude of 20.5 in the R band. Somewhat closer to home, but equally faint, is the dwarf galaxy Leo 15 (also annotated).

The image was taken on 22 Feb 2018 and 13-14 March 2018 and consists of 7hrs of exposure through the luminance filter (84 x 5min subexposures) using an ST2000XM on a 350mm Newtonian at 1584mm focal length. Processing and reduction took place in Pixinsight.

Weather was very poor this spring and I had no chance to get any decent colour data to produce a finished LRGB version – will have to hold this one over until next year…

Field (25’x18.6′) centred at:
RA: 10h 46m 44s
Dec: +11° 49′ 23″
Up is 184° E of N

astroimaging, astronomy, galaxies

M106 in Canes Venatici

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Field Centred at:
RA: 12h 18m 41.0s
Dec: +47° 17′ 57.3″
Field 25.2×18.9 arcmin, Up is 184° E of N

M106 (with NGC4248) - LRGBM106 (NGC 4258) is an intermediate type spiral galaxy located at a distance of 23.7 (± 1.5) million light years in the constellation of Canes Venatici. Also shown in this frame is the small spiral galaxy NGC 4248 (lower left of frame).

M106 was discovered by Pierre Méchain in 1781 and has an active nucleus and is one of the best known Type 2 Seyfert galaxies. It also is host to a water vapour megamaser that is visible in the 22GHz frequency of ortho-H20 (water molecules where the spins of the two hydrogen atoms are aligned). 

M106 also has significant hydrogen emission around the core – one of the brighter “jets” is just visible in the close up (at 150%)  – taking hydrogen alpha data would show this up to a much greater extent, but this is something that will have to follow later when skies are clear!

In June 1995, the following letter was published in Astronomy & Astrophysics from Burbidge concerning two bright Xray sources symmetrically placed about NGC 4258 (M106):  1995A&A…298L…1B

Burbidge found that these objects were in fact quasars, with redshifts of 0.39 (J1218+472) and 0.65 (J1219+473). Burbidge, who worked closely with Fred Hoyle, argues (as does Halton Arp in a later paper), that the association of these QSOs with M106 is not accidental, and that the redshifts arise from the ejection velocities of the objects from the host (pretty quick!).

All three scientists were strong proponents of non-Big Bang cosmologies though, so you may detect a slight bias here: later work (eg , http://iopscience.iop.org/article/10.1086/309327/pdf) appears to suggest one of these (J1281+472) is associated with a cluster at redshift z~0.3, and that X-Ray luminosity and cluster temperatures are entirely consistent. So, this may well be a case of line of sight.

In the field as well (see the image, left), is a further QSO with redshift ~1.04 – theory places this at around 8Gly in a flat cosmology.

 

Image was taken with an ST2000XM through a 14″ Newtonian at f4.53 (fl = 1584mm) from West Oxfordshire on Feb 13th/15th 2018. Exposures lengths are:

Lum: 5h35m (56x5m + 21x3m) 
R: 1h45m (21 x 5m, 2×2 bin)
G: 1h20m (16 x 5m, 2×2 bin)
B: 1h20m (16 x 5m, 2×2 bin)

The luminance data on its own is shown below.M106 (with NGC4248) - Luminance Channel

 

 

 

 

 

EDIT: This image was selected in 2nd place for the “A Galaxy, Far, Far Away” challenge on Stargazers Lounge – see: https://stargazerslounge.com/topic/314249-imaging-challenge-11-galaxies-winners/

astroimaging, astronomy, galaxies

Virgo Galaxy Cluster

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Field centred at (platesolve by nova.astrometry.net):
RA: 12h 26m 15s
Dec:  +12° 52′ 36″
Up is -177 degrees E of N

M86/M84 Region of the Virgo Galaxy ClusterThe Virgo Galaxy cluster is a large nearby cluster of galaxies, that spans over 8 degrees of sky, and consists of over 1300 member galaxies. The cluster forms part of the Virgo super-cluster, of which the Local Group (with the Milky Way, M31, and M33) is an outlying member. 

The cluster is approximately 50MLy distant, and is comprised of three main clumps, with the image here displaying the M86 “subclump” of the “Virgo A” clump. M87 (Virgo A itself), is just off the frame to the lower left. The three largest galaxies in the image above are M86 (centre), M84 (right) and the interacting pair NGC 4435/4438 (left – otherwise known as “The Eyes”). These galaxies make up part of the famous “Markarian’s Chain” which is a series of bright galaxies extending off frame to the top left (north-east). Virgo Cluster - M86/M84 Region, Reverse AnnotatedAlso present in the image above are NGCs 4387, 4388, 4402, 4407, 4425, as well as several IC objects (including the odd blue irregular galaxy IC3355 at the top of the frame) and countless faint objects – some of which are highlighted in the annotated reversed image with galaxies highlighted from the SDSSR8 catalogue down to magnitude 20. 

“The Eyes” make an interesting pair – the smaller (NGC4435) is a barred lenticular galaxy (an intermediate between an elliptical and spiral). The larger NGC4438 is the most distorted of all galaxies in the cluster – with much of the disruption apparently caused by a past interaction with NGC4435. The detection of gas linking NGC4438 and M86 suggests that at some point all three galaxies have had past interactions. Additionally, there is some question as to whether the core of NGC4438 is powered by starburst (which may be as a result of the previous interactions), or whether it is home to an Active Galactic Nucleus, powered by a black hole. 

Data was taken over several nights during March and April 2017 from West Oxfordshire, UK using a WO FLT110, FLAT4 reducer, ST-200XM and Losmandy Titan. LRGB exposures were 240 (24x10min) : 75: 70 :70 (RGB in 5 min subs, 2×2 bin). Unfortunately, the flats didn’t reduce well here, so there was quite a bit of work in trying to eliminate gradients across the image – this may have restricted a little what I was able to pull out of the image data.

astroimaging, astronomy, galaxies

M31, NGC206 and the Bologna Catalogue

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NGC206 Region in M31 - Lum ChannelPresented here is a bit of a “nonsense image” of the Andromeda Galaxy, M31, that I grabbed early in the evening of the 22nd Jan 2017. This was a quick run, mainly while I was waiting for another target to clear the tree near my observatory…!

However, even in an image like this, which only consists of 14x5min exposures through a luminance filter, there is lots to be explored – first it gives me a good idea about future plans for a mosaic (though this will have to wait until the autumn now, and may be a major undertaking…). It also gives a good view of NGC 206, which is a bright star cloud in M31, and I plan to image this alone at longer focal lengths later on. Also, it allows me to explore objects in the Bologna Catalogue 1.

NGC206 Region in M31, with Bologna Catalogue Globular Clusters AnnotatedThis catalogue  is not one that comes immediately to mind when talking about deep-sky objects – but it is a very specialised list describing globular clusters (GCs), candidate GCs and previous candidate GCs in M31. The up to date version of the catalogue is freely available on the Bologna Catalogue website and can be downloaded, manipulated and used as a source of information for the Annotate script in Pixinsight. Presented here in negative format is the south west region of M31, with overlaid markers for the confirmed GCs in the Bologna Catalogue v.5 (with associated V magnitudes) in red, as well as a few small PGC galaxies that loiter in the field marked in light blue. There are 181 marked objects alone in this field – most of which have been successfully captured using just a small 4 1/2″ refractor!

Image details:

ST2000XM, William Optics FLT110 + FLAT4 reducer
14x5min, L filter
Reduced and processed in Pixinsight

References

1. Galleti S., Federici L., Bellazzini M., Fusi Pecci F., Macrina S.: “2MASS NIR photometry for 693 candidate globular clusters in M31 and the Revised Bologna Catalogue (V.1.0)”, Astron.&Astrophys., 2004, 416, 917 (G04)