THE B⚫IS: Tracking HypervElocity Blackh⚫le-Origin stars

High velocity stars

Group members and roles:

George Greenyer – PI/coordinator

Josh Smith – Data analysis

Keenan Wright – Administrator

Nathan Wright – Coding

Rhys Jaques – Report lead

Antonio Coulton – Theory Lead

Weekly Research Updates:


By Rhys Jaques

We are THE B⚫IS! We shall be studying the nature and origins of high velocity stars; stars which are, through several possible mechanisms, ejected from their home system at incredible speeds.

The most well documented of these mechanisms is called the Hills’ Mechanism. In the Hills’ mechanism a binary star system undergoes an interaction with a black hole in which one of the stars is captured by the black hole and the partner star subsequently flies off at high velocity. Such interactions have been observed to result in stars travelling with velocities of up to 1000km/s relative to the rest of the galaxy.

We shall be analysing data from GAIA and building simulations in order to model the origins of high velocity stars and build on our understanding of this fascinating phenomenon.


By Rhys Jaques

Today the project began in earnest. After a short delay settling a territorial dispute with the dastardly TEABAG (a neighbouring group project) interlopers we settled down at our work stations.

We have made significant progress with the simulation, with a now functional n-body simulation capable of modelling a non-binary star system, along with momentum conserving collisions resulting in an idealised confluence of mass.

Our head data analyst, Josh Smith, also made progress with plotting software TOPCAT, producing a HR diagram of the stars in our catalogue.

We are also fortunate to provide you with an exclusive interview with THE B⚫IS own coding lead, Nathan Wright. Brimming with enthusiasm, obviously eager to get back to work, we sat down to begin the interview.

‘I really enjoy fun.’

Rhys: “Hi, thanks for joining me here today for this interview.”

Nathan: “What?”

Rhys: “So you’re THE B⚫IS’ coding lead, what exactly does that entail?”

Nathan: “I’m currently opening SPYDER…”

Keenan: “No you’re not. Your screen says no internet!”

Nathan: “I’m also opening Chrome…”

Rhys: “Well it is obvious that you’re very busy, before we conclude can I get a comment on how you feel about the project in general?”

Nathan: “I really enjoy… fun.”

Join us next week for an exclusive interview with THE B⚫IS administrator, Keenan Wright, and the thrilling conclusion to the greatest dilemma of our time: Will Nathan ever connect to eduroam?


By Rhys Jaques

I know our readers must have been very on edge, so let me begin by allaying your doubts and assuring you that Nathan did, in fact, successfully connect to eduroam.

Now onto today’s update.

Tensions with TEABAG are running high, with the territorial disputes resulting in advances and retreats along the contested border. We have successfully captured an unscrupulous TEABAG spy, undoubtedly trying to steal our technology in order to fuel the forces of bourgeois reaction.

Captured TEABAG spy. Who knows what evil schemes have been enacted by this saboteur.

Today has been very fruitful with regards to progress with the project. On the coding front, Nathan has successfully implemented the Barnes-Hut algorithm, allowing our simulation to operate significantly faster by breaking it into subdivisions.

George, Antonio and Josh have successfully reduced our database of over 3 million stars to 67 viable hypervelocity stars. They plotted a graph, apparently called Carl, showing a right-ascension, declination sky-view in order to show the spread of these stars.

Carl“. This graph plots all 3 million of the stars in our database. In this graph the blue dots represent stars with a velocity over 500km/s, but these stars are too close to Sag A* to ensure that their velocity has been imparted by one of the mechanisms we are studying and not just because they have such a small orbital radius with regards to the galactic centre. The yellow dots represent stars with velocities greater than 500km/s that are sufficiently far from Sag A* that we can confidently conclude that they are hypervelocity stars which have experienced one of the mechanisms that our report is investigating.

In the meantime, me and Keenan have written the introduction of the report, summarising the 5 mechanisms which are known to give rise to high velocity stars, 3 of which can potentially give rise to hypervelocity stars.

Speaking of Keenan, I was fortunate enough to get an interview with him, included below:

“As sitting Minister of Defence… I cannot comment”

Rhys: “Thanks you for joining me for this interview”

Keenan: “Oh, is it happening now?”

Rhys: “Yes well i’m sure you’ve got a loaded schedule so lets get on with it”

Keenan: “Sure thing”

Rhys: “So what is your role within the group exactly?”

Keenan: “Admin”

Nathan: “Is that right, is it?”

Keenan: “I hope so. It’s what i’ve been doing…”

Rhys: “So what does that entail exactly?”

Keenan: “Doing the administration stuff… Notes, schedules… etc.”

Rhys: “Right well, err, thanks for that elaboration, how do you think the group project is going overall?”

Keenan: Shrugs “Amazing, we are… except Nathan, Antonio, Rhys, Josh and George, the rest are amazing.”

Rhys: “…”

Keenan: “No, get rid of that, that was off the record!”

Rhys: “…So do you have any comments on the escalating tensions with TEABAG?”

Keenan: “It would not be proper for me to comment at this time. As sitting minister of defence… I cannot comment.”

Nathan: “You’re useless Keenan”

Rhys: “Well, i’ll let you get back to your work now, i’m sure you have lots to do.”

Keenan: “Yeah, i’m currently writ-“

Rhys: “Join us next week for an exciting interview with group coordinator George Greenyer.”

Lastly, we used a random list generator to determine the order of our names on the report. As fate would have it, yours truly was selected as Author One. Accusations of possible rigging have been denied by Author One.


The captured TEABAG spy made an unsuccessful escape attempt . The prisoner was killed in the process.

And nothing of value was lost…


By Rhys Jaques

Nathan is missing. His status is unknown. Suggested possibilities range from being blown into the ocean by Storm Ciara to capture by TEABAG espionage agents. We will provide updates on this story as new information becomes available.

In the meantime, TEABAG have made several acts of aggression against our peaceful land in an attempt to avenge their deceased would-be-escapee. They have launched an attack on our Dea-Peace Star and have undergone a significant military build-up on their side of the border. The possibility of de-escalation seems increasingly unlikely.

Our benevolent Peace Star, still ablaze in the aftermath
of the brutish attack by TEABAG

On the project front, we have successfully made our own diagrams to provide additional clarity to our explanations of the Bound Scenario and Slow Intruder Scenario. These were made by yours truly on the incredibly professional application MS Powerpoint.

This magnificent diagram depicts the Bound Scenario mechanism, in which a black hole approaching a black-hole/star system destabilises the orbit in such a way that the star is ejected at high velocity.
This equally magnificent diagram depicts the slow intruder scenario, in which a star passes through a black hole binary of unequal mass, and its trajectory is therefore attracted towards the more massive black hole, in this case, BH2.

Onto our data analysis. Antonio has produced the following graph of our catalogue of 3 million stars, depicted in a Gaussian distribution of their total velocities. From this graph we can calculate that the portion of stars we are considering to be hypervelocity stars (Over 500km/s) are of ~10σ standard deviations from the average velocity of our catalogue.

Logarithmic Gaussian distribution of the
total velocities of our star catalogue.

We now present our exclusive interview with PI/Coordinator George Greenyer.

“Yeah. He’s dead. I mean, I definitely don’t know that, but he might be dead.

George: What do you want to know?

Rhys: So… Nathan is missing…

George: Yeah. He’s dead. I mean, I definitely don’t know that, but he might be dead. Probably.

Rhys: Is that a particularly big loss for the project?

George: It’s been quite nice actually, it has been much calmer and everyone is being quite nice to each other.

Rhys: So your role is PI/Coordinator, right?

George: Yes.

Rhys: What does the PI actually stand for? I’m assuming it’s not private investigator…

George: It’s actually a state secret.

Rhys: Ok. I’ll ask no more then. Can you tell us anything about what your role entails though, or is that classified as well?

George: Usually it means I yell at people and get them to do what I tell them, sometimes I help out but… mostly it’s just yelling at people.

Rhys: Have you been particularly productive so far today?

George: I have actually. I have successfully written working python code, which is madness for me.

Rhys: Yeah. I assume it’s been quite a while since you’ve used python?

George: Yeah, I tend to avoid things which cause me pain, like sharp objects, hot surfaces, and… python.

Rhys: Have you got any thoughts about the unscrupulous acts of aggression from TEABAG?

George: Well i’m looking at one right now, and I reckon I could take him!

TEABAG Interloper: If your code works you probably could…

Rhys: Alright, well I think that’s probably all for now, thanks for joining me for this interview.

George: You’re wel-

Rhys: Join me next week for an interview with ‘The All-Knowledgeable Lord President and Supreme Leader Antonio Coulton.

In memoriam


By Rhys Jaques

I am sad to report that Nathan has been confirmed as having died in defence of the Peace Star. Fortunately Nathan’s training in the force has allowed him to come back more powerful than ever, as a force ghost.

Uh… No.

I was fortunate enough to have the opportunity to ask the freshly transparent Nathan a single question.

Rhys: Hey Nathan, can you give me a comment on what dying is like?

Nathan: Uh… No.

This new information on the realm beyond death is sure to cause many tumultuous debates in philosophical and theological communities.


By Rhys Jaques

Comrades, it is with a heavy heart that I must inform you that TEABAG have stooped to yet another new low. From our undercover operatives we have received intelligence proving beyond any doubt that TEABAG is manufacturing chemical weapons

Here is the incontrovertible proof that TEABAG is producing chemical weapons.

This flagrant violation of the Geneva convention so close to our border after the many unwarranted acts of aggression by TEABAG leaves us with no choice but to formally declare war against them. THE B⚫IS Central Committee does not make this decision likely, but have come, after much deliberation and debate, that it is the best path forward to ensure the prosperity and security of our peaceful nation. The civilians of TEABAG will also benefit from this; our annexation of their territory will bring about great leaps forward in their quality of life and material conditions.

Apropos to the astrophysics project, myself and Keenan have discovered another high velocity star creating mechanism which we had previously overlooked. This mechanism involves the close passage of a dwarf galaxy past a larger galaxy. The interaction of tidal gravitational forces can result in a star being ejected from the dwarf galaxy into the halo of the larger galaxy as a high velocity star.

On the coding front, Nathan has been able to simulate the trajectories of 100s of suspected high velocity stars over a period of several billion years.

We now present our interview with Supreme Leader Antonio Coulton.

“If they can’t evolve fast enough, that’s their problem”

Antonio: Before we begin, I would just like to say that the alleged attack on the TEABAG medical tent has nothing at all to do with THE B⚫IS quite clearly this was an inside job as we do not have the means to carry out such an attack.

Rhys: Right well thank you for that clarification, I’m sure such information was eagerly awaited by the international community. Recent information has come to light regarding the manufacture of chemical weapons in TEABAG territory. Would you care to comment on this new intelligence?

Antonio: Of course. Such acts are not acceptable and THE B⚫IS will definitely be taking pre-emptive defensive action, including, but not limited to, espionage, propaganda campaigns and nuclear warfare.

Rhys: Do you have anything to say to allay the fears of those who worry such a war could result in the extinction of all human and teacup life?

Antonio: All humans and teacups of the world need not worry as we have only love nukes which will be spreading peace and compassion throughout the contested territory.

Rhys: Well i’m sure that will put everyone’s minds at rest. On a more positive note, the B⚫IS have recently embarked on a green initiative. Would you like to elaborate on what exactly is being done to ensure the sustainability of energy production within the nation?

Antonio: In the next ten years THE BOIS will construct 5 nuclear power stations as well as 2 new hydroelectric dams. In addition, we recently finished the construction of our nation’s first hydroelectric dam.

Rhys: Such an act surely fills the world’s hearts with hope that we can overcome the plight of impending climate disaster.

Antonio Indeed. We do love turtles.

Rhys: What are your thoughts on polar bears?

Antonio: I mean if they can’t evolve fast enough, that’s their problem.

Rhys: Nathan has recently become intangible and transparent, has this had any noticable effects on his productivity and dedication to the party line?

Antonio: Until the recent death of Nathan I never believed in ghosts, there just wasn’t a physical explanation. This is why, given the recent resurrection of Nathan as a force ghost, I will be dedicating all of my time to the research of ghosts. Nathan has now become much more productive as he no longer needs sustenance or sleep. He has successfully simulated the future trajectory of 100s of suspected high velocity stars.

Rhys: It sounds like progress on the simulation is coming along well. Do you think the project is on track to finish on time?

Antonio: Hold on, let me consult my magic eight ball.

Rhys: Ok, i’ll give you a second.

Antonio: It says ‘most likely’
Rhys: Well that’s a relief. Thanks for taking time out of your very busy schedule for this interview. I’ll let you go back to governing the country now.

Antonio: Aye, absolu-

Rhys: Join us next week for an interview with Lead Data Analyst Josh Smith.


By Rhys Jaques

I must apologise for the late upload of this blog update, but we have been without internet, forced to retreat into underground bunkers in order to avoid an unscrupulous attack against us by TEABAG.

On the 27th George successfully produced a graph of escape velocity against distance from the galactic centre, as seen below:

I meanwhile derived an equation to calculate the net effect of dark matter on a simulated high velocity star, using geometric arguments and the following diagram to produce the subsequent equation.

Note that this is the final version of the equation produced on 05/03/2020. The one produced on 27/02/2020 had some which we have since corrected.

Nathan successfully managed to recreate the production of a high velocity star through the Hills’ mechanism in his code.

Finally, I interviewed Josh, as seen below.

Rhys: Thanks for joining me today.

Josh: Yeah, anytime.
Rhys: So how does it feel to be reaching the end of labs?
Josh: Stressful.
Rhys: Are you not relieved that you won’t have to come in for 7 hours anymore?
Josh: Yeah i’ll be relieved when it’s over, but i’ve not had time to get started on my section of the report. So it’s… not very good.

Rhys: So what exactly is your role within the group?
Josh: I am Error Man!
Rhys: And what type of superpowers does such a role bestow?
Josh: Err… what does that mean?
Rhys: … Nevermind I guess… Any general comments on the project?

Josh: I get frustrated that things aren’t moving as they have been, and ‘certain’ people haven’t been putting their equations in the data sheet
George: what are you looking at me for?
Rhys: The conflict with teabag appears to have cooled down, any thoughts?
Josh: I try and stay out of these matters, i’m a conscientious objector. I am a man of peace.
Rhys: Does your principle of non-violence ever conflict with the obligation to use your error analysis superpowers for the greater good?
Josh: These are just words, they have no meaning.
Rhys: I didn’t realise you had transcended the medium of conversation, perhaps I too shall have to invest in the magic of error propagation

Rhys: So how do you respond to the allegations against you of revisionism and deviation form the party line?
Josh: No comment (leaves)
Rhys: I think that speaks for itself. Join me next week, for an the most exciting interview guest yet, Myself!

At the conclusion of this interview the air-raid sirens warned us of an impending TEABAG attack and we were forced to retreat to the nuclear bunkers.


By Rhys Jaques

Today we were finally able to exit the bunkers, with the radiation having reduced to bearable levels. In response to TEABAG’s attack against us we have responded in kind. Their land has now been reduced to rubble. The handful of survivors have been vassalised and we are now proud to announce the birth of a new nation; THE DEMOCRATIC PEOPLE’S REPUBLIC OF TEAB⚫IS.

Meanwhile I have made corrections to the equation derived in the last update, which perhaps took a tad longer than it should have done.

Nathan has been simulating a wide array of stars using our now finalised code, with over 1000 stars being simulated as I type this.

And finally, here is our long awaited interview with myself:

Rhys: Hi Rhys, thank you for joining me here.

Rhys: To be honest I had somewhere else I wanted to be but I can’t seem to get away from you.

Rhys: So what is your role in the group?

Rhys: I’m the report lead.

Rhys: And what does that entail?

Rhys: I have to write a large portion of the report. I also have to write this crappy blog…

Rhys: Crappy?! I’ll have you know this blog has been reasonably well received!

Rhys: I think that’s more a comment on people’s low standards rather than the quality of the blog…

Rhys: I don’t really need all this negativity to be honest… Lets change topic. So… the war with TEABAG is over, THE B⚫IS have annexed their territory and absorbed the survivors into their populace. What are your thoughts on this?

Rhys: It’s a mixed bag. On the one hand a dark period in our short history is now behind us. However, I question the wisdom of the Supreme Leader‘s decision to immediately declare war against BAHAMAS. I think we could have done with a period of peace in order to rebuild our productive forces. Don’t tell him I said that though.

Rhys: Don’t worry, my lips are sealed. To be honest, I’m inclined to agree. With that I think the interview is finished. Thank you for joining me here today!

Rhys: Always a pleasure with you, Rhys!