Snake in the clouds—astronomers discover a new dwarf galaxy in the Magellanic Bridge

April 30, 2018 by Tomasz Nowakowski, Phys.org report
The density of main sequence turn-off in the Magellanic Clouds region. The location of newly discovered dwarf galaxy in between Large Magellanic Cloud (on the left) and Small Magellanic Cloud (on the right) is marked by a red dashed circle. Credit: Koposov et al. 2018.

An international group of astronomers reports the detection of a new dwarf galaxy in the so-called Magellanic Bridge – a stream of gas linking the two Magellanic Clouds. The newly found galaxy, designated Hydrus 1, is described in a paper published April 17 on the arXiv pre-print server.

The new galaxy was found in the Hydrus constellation. It is a small a small constellation in the deep southern sky. Its name means a "male water snake." Therefore, the astronomers refer to the newly discovered galaxy as a "snake in the clouds."

Hydra 1 was discovered by a team of researchers led by Sergey E. Koposov of the Carnegie Mellon University. They used the Dark Energy Camera (DECam) mounted on the 4-m Blanco Telescope located at Cerro-Tololo Inter-American Observatory (CTIO) in Chile to observe the region between the Small (SMC) and the Large Magellanic Cloud (LMC).

Analysis of spectroscopic data obtained by DECam resulted in the identification of a new ultra-faint dwarf galaxy.

"In this paper we presented the discovery and detailed analysis of a new ultra-faint Milky Way satellite, called Hydrus 1," the researchers wrote in the paper.

The study reveals that Hydrus 1 is a mildly elliptical and ultra-faint system, located some 90,000 light years away from the sun and around 78,000 light years away from the LMC. The galaxy has an absolute magnitude of –4.7 a circularized half-light radius of approximately 163 light years, and a surface brightness noticeably brighter than many typical ultra-faint dwarf spheroidals.

According to the astronomers, these parameters indicate that Hydrus 1 is most likely a dwarf galaxy; however, it may also be an extended globular cluster.

The observations found that Hydrus 1 has an old, metal-poor stellar population with several blue horizontal-branch stars and two RR Lyrae variables. The researchers also noted that the system is dark matter dominated, what once more suggests that it may be a globular cluster with a small amount dark matter or a that lost some dark matter due to tides.

When it comes to chemical composition, the study found that Hydrus 1 is rather metal poor, with mean metallicity of –2.5. What is noteworthy, the system has one carbon-enhanced extremely metal-poor star with metallicity of about –3.0 and a carbon to iron abundance ration of around 3.0.

"This level of carbon enrichment makes it one the most carbon-enhanced stars known in both the Milky Way halo and the dwarf ," the paper reads.

The researchers concluded that Hydrus 1 is most probably a part of the Magellanic family of satellites that were brought into our home galaxy by the Magellanic Clouds. This assumption is based on the spatial position and the observed line-of-sight velocity of the system. However, more observations are still needed to definitely confirm this hypothesis. Therefore, the authors of the paper hope that the upcoming Gaia Data Release 2 (DR2), containing data obtained by ESA's Gaia satellite, will be helpful in uncovering more details about the disputed connection between Hydrus 1 and the LMC.

Explore further: New stellar stream discovered by astronomers

More information: Snake in the Clouds: A new nearby dwarf galaxy in the Magellanic bridge, arXiv:1804.06430 [astro-ph.GA] arxiv.org/abs/1804.06430

Abstract
We report the discovery of a nearby dwarf galaxy in the constellation of Hydrus, between the Large and the Small Magellanic Clouds. Hydrus 1 is a mildy elliptical ultra-faint system with luminosity MV∼ -4.7 and size ∼ 50 pc, located 28 kpc from the Sun and 24 kpc from the LMC. From spectroscopy of ∼ 30 member stars, we measure a velocity dispersion of 2.7 km/s and find tentative evidence for a radial velocity gradient consistent with 3 km/s rotation. Hydrus 1's velocity dispersion indicates that the system is dark matter dominated, but its dynamical mass-to-light ratio M/L ∼ 66 is significantly smaller than typical for ultra-faint dwarfs at similar luminosity. The kinematics and spatial position of Hydrus~1 make it a very plausible member of the family of satellites brought into the Milky Way by the Magellanic Clouds. While Hydrus 1's proximity and well-measured kinematics make it a promising target for dark matter annihilation searches, we find no evidence for significant gamma-ray emission from Hydrus 1. The new dwarf is a metal-poor galaxy with a mean metallicity [Fe/H]=-2.5 and [Fe/H] spread of 0.4 dex, similar to other systems of similar luminosity. Alpha-abundances of Hyi 1 members indicate that star-formation was extended, lasting between 0.1 and 1 Gyr, with self-enrichment dominated by SN Ia. The dwarf also hosts a highly carbon-enhanced extremely metal-poor star with [Fe/H] ∼ -3.2 and [C/Fe] ∼ +3.0.

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cantdrive85
1 / 5 (6) Apr 30, 2018
Beads on a string, that is the expectation of galaxies that are created along these galactic Birkeland currents. This is also how stars form on a smaller scale.
sparcboy
5 / 5 (3) Apr 30, 2018
Just curious as to what this discovery does to mass and dark matter calculations. They find hundred and thousands of new galaxies full of hundreds of thousands and millions of stars billions of light years away. And now we find a dwarf galaxy previously unknown that is, relatively speaking, in right in our own back yard.

If all this time we've been unaware of a galaxy that close, how many more galaxies are there in the universe?
andyf
5 / 5 (5) Apr 30, 2018
Oh dear, more EU woo from cd85.

"Cosmologists and astrophysicists who have evaluated plasma cosmology have rejected it because it does not match the observations of astrophysical phenomena as well as current cosmological theory. Very few papers supporting plasma cosmology have appeared in the literature since the mid-1990s." - https://en.wikipe...osmology

jonesdave
3.5 / 5 (8) Apr 30, 2018
Beads on a string, that is the expectation of galaxies that are created along these galactic Birkeland currents. This is also how stars form on a smaller scale.


What galactic Birkeland currents?
andyf
5 / 5 (6) Apr 30, 2018
@sparcboy:
It's not going to make much difference to the calculations primarily because it is so tiny (as galaxies go). 163 light years half-light radius is next to nothing on the galactic scale - no wonder we only just noticed it!
cantdrive85
1.6 / 5 (7) Apr 30, 2018
Cosmologists and astrophysicists who have evaluated plasma cosmology...

The wikistupidia article needs an adjustment;
"Plasma ignoramuses who have evaluated plasma cosmology are basing their conclusions from a position of utter ignorance so their opinions on the matter can be ignored completely."
Besides, if they did acknowledge the legitimacy of PC/EU then they would all be out living on the streets because their skills/education would be useless in describing reality.
andyf
5 / 5 (4) Apr 30, 2018
Besides, if they did acknowledge the legitimacy of PC/EU then they would all be out living on the streets because their skills/education would be useless in describing reality.


ROTFLMAO!

So you're saying they'd be like you?
TheGhostofOtto1923
5 / 5 (5) Apr 30, 2018
Speaking of galactic sky serpents (and mystical EU wizardry)

Happy Walpurgisnacht
andyf
5 / 5 (5) Apr 30, 2018
Speaking of galactic sky serpents (and mystical EU wizardry)

Happy Walpurgisnacht


Good lord, is it that late?
jonesdave
3.3 / 5 (7) Apr 30, 2018
Plasma ignoramuses ..............


Such as Don Scott? And Wal Thornhill?
IMP-9
4.4 / 5 (7) Apr 30, 2018
Just curious as to what this discovery does to mass and dark matter calculations. ...


Finding more galaxies doesn't really affect the total amount of matter or dark matter in the universe, according to standard theory. Determining how much matter there is in the universe by counting galaxies is very hard, most of the mass isn't believed to be in stars and you can only estimate masses with dynamics to some radius. It also doesn't tell you about the matter outside galaxies. Instead the best understanding of the total amount of matter in the universe comes from the Cosmic Microwave Background and primordial nucleosynthesis, both of these test the very early universe before there were galaxies or stars. These tests don't depend on how many galaxies we measure today so the overall ratio is unchanged. The only way the ratio would be affected by galaxy counts is if you found there were too many baryons in the current universe for standard cosmology, which is not the case.
cantdrive85
1 / 5 (4) Apr 30, 2018
Happy Walpurgisnacht

This is especially ominous for blotto and jonesdumb as I believe their mothers were burned at the stake on this day.
IMP-9
4.5 / 5 (8) Apr 30, 2018
Finding more faint galaxies is interesting from a dark matter perspective even if it doesn't affect the overall ratio. What is quite a hot topic in dark matter research is comparing the Milky Ways population of satellite galaxies to those produced by state of the art simulations. There have been various claims of discrepancies and counter claims. These galaxies should be dominated by dark matter and thus they provide neat tests of theory. It's quite an active field. One interesting recent tentative discovery is that the satellite galaxies of the Milky Way and Andromeda may not be representative. Whereas most of the large nearby dwarf galaxies are not star-forming, a recent survey however showed similar galaxies were almost all star-forming.
sparcboy
5 / 5 (3) Apr 30, 2018
@andyf ..... Well, I didn't state it very well, but the premise being if we missed this galaxy in our own backyard, how many more galaxies like it have we missed? There must be hundreds of millions across the universe. That adds up to a little bit of mass.
TheGhostofOtto1923
5 / 5 (2) Apr 30, 2018
This is especially ominous for blotto and jonesdumb as I believe their mothers were burned at the stake on this day
Well my mother was a nun so is ok
cantdrive85
1 / 5 (4) Apr 30, 2018
A witchcraft encanting whore nun, sounds about right.
RealityCheck
1 / 5 (7) Apr 30, 2018
@IMP-9.
the best understanding of the total amount of matter in the universe comes from the Cosmic Microwave Background and primordial nucleosynthesis,
Neither of which is valid interpretation of observations.

We NOW know observed CMBR wavelengths, AND Nucleosynthesis Ratios, are due to ONGOING processes; and NOT due to some hypothesized 'primordial' Big Bang event (which is increasingly UN-tenable mathematical/metaphysical conjecture (ask Penrose and Steinhardt). I've even explained where the (1)CMBR and (2)NUCLEO-SYNTHESIS RATIOS actually COME from; ie:

(1)CMBR:

- ongoing Extreme Gravitational Redshifting" of photons originating from every 'extreme feature', such as Neutron-Star Surface, and every BH's near-Even-Horizon region, over eons; and

- ongoing Extreme Doppler Redshifting of photons from every natural COSMIC MASER and POLAR-JET that is pointing its radiation/ejecta away from us and 'backscattering' doppler-redshifted to CMBR to our detectors.

cont...
RealityCheck
1 / 5 (7) Apr 30, 2018
@IMP-9 cont...

(2)NUCLEO-SYNTHESIS (Hyrogen/Helium) RATIOS:

- ongoing 'recycling' of energy-matter via every extreme POLAR JET SYSTEM; which deconstructs huge quantities of material to Quark-Gluon state (like occurs in our LHC); which QG-Plasma quickly re-forms into simple Hydrogen/Helium which is scattered into deep space regions, and MIS-IDENTIFIED as 'pristine' nucleosynthesis material from 'BB fantasy'.

HENCE all BB-dependent 'interpretations', 'claims', 'estimates', 'conclusions' and 'problems', are ARTIFACTS OF UNTENABLE CONJECTURES 'inspired' by Big Bang-derived NONSENSE.

Meaning that any and all assertions/studies pretending to treat/test 'primordial' Big-Bang-assumed 'information' contained in CMBR and NUCLEO-SYNTHESIS RATIO interpretations/calculations, are just GIGO-from-GIGO 'exercises' forming a nonsense-generation-chain leading back to BB-fantasy-contaminated 'interpretations' of data.

Please update your REALITY base; avoid defaulting to parroting GIGO. :)
RealityCheck
1 / 5 (7) Apr 30, 2018
@IMP-9.
Finding more faint galaxies is interesting from a dark matter perspective even if it doesn't affect the overall ratio. What is quite a hot topic in dark matter research is comparing the Milky Ways population of satellite galaxies to those produced by state of the art simulations. There have been various claims of discrepancies and counter claims. These galaxies should be dominated by dark matter and thus they provide neat tests of theory. It's quite an active field. One interesting recent tentative discovery is that the satellite galaxies of the Milky Way and Andromeda may not be representative. Whereas most of the large nearby dwarf galaxies are not star-forming, a recent survey however showed similar galaxies were almost all star-forming.
Reads as 'rationalization-for-failure', mate. Worse: 'rationalization-for-repeated-failure'. A 'wanting it every which way' set of excuses/diversions for/from the reality of doomed 'exotic'-DM fantasies.

Give it up, mate. :)
cantdrive85
1 / 5 (7) Apr 30, 2018
@sparcboy,
Unless they find these galaxies in the hundreds if not thousands embedded within other galaxies to explain the anomalous observed rotation curve of the galaxies. Recall DM was initially invented to explain the dynamics of galaxies which falsified the guess that gravity was valid at these scales.
There is a model that matches observations very well though;
http://www.ptep-o...1-13.PDF
http://www.ptep-o...3-01.PDF
jonesdave
3.8 / 5 (10) Apr 30, 2018
@sparcboy,
Unless they find these galaxies in the hundreds if not thousands embedded within other galaxies to explain the anomalous observed rotation curve of the galaxies. Recall DM was initially invented to explain the dynamics of galaxies which falsified the guess that gravity was valid at these scales.
There is a model that matches observations very well though;
http://www.ptep-o...1-13.PDF


Lol. No it doesn't! Not even close.
jonesdave
3.8 / 5 (10) Apr 30, 2018
We NOW know observed CMBR wavelengths, AND Nucleosynthesis Ratios, are due to ONGOING processes;


Really? Where do we know this? Link please.
RealityCheck
1 / 5 (5) Apr 30, 2018
@cantdrive85.
@sparcboy (ie, @jonesdave?),...

Recall DM was initially invented to explain the dynamics of galaxies which falsified the guess that gravity was valid at these scales.
There is a model that matches observations very well though;
http://www.ptep-o...1-13.PDF
It doesn't help scientific accuracy/understanding if you are going to sneak in your own 'version' of what distances gravity is or isn't valid in. Please understand that known non-Kepler mass/gravity distributions/regimes, combined with all the NORMAL 'previously dark' matter (which we are finding now, but missed early on because our instruments were not up to the job of 'seeing' it until now), explains all those so-called 'anomalies (which aren't any such thing when all ordinary matter quantities/distributions is increasingly being taken into account) amply explains it and makes all old/simplistic/ignorance-based 'problems' and 'anomalies' springing from incomplete/misinterpreted data.
RealityCheck
1 / 5 (5) May 01, 2018
@jonesdave.
We NOW know observed CMBR wavelengths, AND Nucleosynthesis Ratios, are due to ONGOING processes;
Really? Where do we know this? Link please.
For a start, go to PO thread...

https://phys.org/...ack.html

...and read @antialias's effective acknowledgement that BH's near-EH-regions Redshift photons extremely (which logically would includes gravitatinal redshifting to CMBR range of wavelengths, yes?). I therein posted my thanks to @antialias for that 'assist'.

Anyhow, the mainstream literature is replete with many acknowledgements regarding how BHs near-EH-region gravitationally redshift extremely.

And also re Galactic BH Polar Jets spewing out energy-matter into deep intergalactic/inter-gal-cluster space (as well as overall 'galactic winds' doing likewise) at relativistic velocities.

The obvious implications as current sources of CMBR/Nucleosynthesis-Ratios has been IGNORED due to BB/Inflation BIAS. :)

jonesdave
3.7 / 5 (9) May 01, 2018
^^^^^^No, just link me to a paper where this is outlined. Not the comments section of a sci-news website. You know, something peer-reviewed, as opposed to word salad.
RealityCheck
1 / 5 (5) May 01, 2018
@jonesdave.
No, just link me to a paper where this is outlined. Not the comments section of a sci-news website. You know, something peer-reviewed, as opposed to word salad.
I have many times already reminded all here that I am not here to 'spoonfeed' anyone stuff that they can readily ascertain for themselves (if they really are 'fair dinkum' about objective science discussion).

The mainstream papers about extreme BH near event horizon regions gravitationally redshifting to extremes; and about galactic polar jets/winds spewing energy-matter into deep space, are easily searched for (if you are fair dinkum, and not just wanting to waste my time on things you should confirm for yourself).

And, again, I stress: if you and others are not up-to-date and well-read in the relevant points/subject matter raised, then its your problem. You may not be totally to blame for not 'connecting the dots'; due to BIASES/GIGO inculcated by BB/INFLATION etc 'dogma'.

Rethinkitall, mate. :)
TheGhostofOtto1923
5 / 5 (1) May 01, 2018
A witchcraft encanting whore nun, sounds about right
Owww and I almost believe in your voodoo EU.

Don't worry that dead skunk in your toilet probably came from your anus.

Happy holiday! Burn a tree for satan!
https://youtu.be/_U82kirAlWU
jonesdave
3.7 / 5 (6) May 01, 2018
Rethinkitall, mate. :)


Translation: "There is zero proof of the CMB being due to recent activity. I just made that up, and have no evidence for it."
Cranks..............sooooo predictable.
RealityCheck
1 / 5 (4) May 01, 2018
@jonesdave.
Rethinkitall, mate. :)
Translation: "There is zero proof of the CMB being due to recent activity. I just made that up, and have no evidence for it."
Mate, do you realize you tacitly admit you are not up to speed with the new knowledge/understandings which have come since the early days; when the old/naive/simplistic mathematical/metaphysical stuff you keep defaulting to was invented?

Don't you know?---

* Astronomical MASER (Microwave Laser) across the universe have been emitting Extremely Doppler Redshifted (CMBR range) photons, for EONS;

* Every BH and NS feature's near surface/EH region Extremely Gravitationally Redshifts photons to CMBR range, for EONS.

* Inter-galaxy/-cluster deep space has contents/processes/states which attenuate much radiation to various redshift (and blueshift) states, some of which is being redshifted to CMBR range.

Old/simplistic views are so 'yesterday'. As are emotional kneejerks/insults. :)

Get up to date, mate. :)

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