For PhD Researchers

/For PhD Researchers
For PhD Researchers 2024-04-25T11:34:06+00:00

This is a very brief to do list for your first days in Germany. Much more information is available on the portal of the federal government “Make it in Germany”. Also because the information there is always up to date, we recommend that you check there.

Your contract

When arriving at your new workplace, you should first contact your group secretary or the international office at the MPIfR in order to sign your research contract or stipend contract if you have not done so. IMPRS researchers receive 3 years of guaranteed funding, with a probation period of 6 months. If you have a research contract, it comes with a series of benefits: annual leave, sick leave and maternity leave, contribution of the employer to health and accident insurance and a pension scheme.

Health insurance

In Germany, health insurance is mandatory. For researchers with a research contract, this needs to be an insurance from the public health service (“Gesetzliche Krankenversicherung”) and your employer will pay part of the costs. When you receive your contract, you will be helped in contracting an insurance. It is strongly recommended to buy an additional international health insurance covering expenses worldwide (less than 20 Euros per year) and to have a liability insurance (about 60 Euros/ year).

Address Registration

Everyone who stays in Germany for longer than 3 months must register at the Resident Registration Office (“Einwohnermeldeamt” in German). This should be done within 14 days after arrival. You have to inform the Resident Registration Office each time you change your address and when you leave Germany. For researchers at the MPI please contact the MPIfR Welcome Office; others: ask at your institute secretary.

Visa and Residence Permit

All non-EU citizens should have entered the country with an national visa and must be converted after arrival into a residence permit. The respective immigration office (“Ausländerbehörde” in German) is responsible for the conversion. Please do no apply for a Schengen-/Tourist Visa. For researchers at the MPIfR please contact the MPIfR Welcome Office; others: ask at your institute secretary.

Open a Bank Account

To open a bank account you can choose any bank. Please note that many banks request a confirmation of your registration in Germany and often a valid residence permit.


Unfurnished rooms/flats here are just that: completely unfurnished (i.e. they don’t even have lighting fixtures!). Sometimes unfurnished apartments have built-in kitchen facilities (sink, refrigerator, cooking stove). The rent for a furnished apartment or a flat for a single person is approx. 550 € per month.

All-inclusive rents are not the rule. Normally the rent consists of two parts: the basic rent + a monthly prepayment for incidental expenditures (= “Nebenkosten”), such as waste disposal, street cleaning etc. You need to find out whether or not Nebenkosten include heating and water. Once a year you will be given a detailed accounting of all the Nebenkosten. After deduction of the monthly prepayment, this either results in a refund or an additional payment. Rent always has to be paid in advance each month. It is advisable to arrange with your bank for an automatically transfer the rent every month (= Dauerauftrag).

Electricity/ Internet:  Usually each tenant makes his/her own contract with the provider. For electricity, a  certain amount will be estimated, which has to be paid every month. Once a year a  settlement is made.

Along with the first payment of the monthly rent usually a deposit (“Kaution”) amounting to 2x (sometimes 3x) the basic rent has to be paid.  On termination of the lease, the deposit will be repaid after deduction of any amount needed for any necessary repairs or renovations (sometimes several months after you have moved out).

You may start checking at the MPIfR international office what housing offers are presently available (there are quite a number of landlords who notify us when they have vacancies). You can search online portals such as  or  ( has been integrated into the platform “housinganywhere”) and (choose Bonn as city (Stadt)). Filter for WG-Zimmer (shared flat rooms) or 1-Zimmer-Wohnung (1 room flat) Wohnung (flat with more than 1 room).

German Classes

Even though speaking German is not required at our IMPRS, we strongly recommend to take German lessons. The partner Universities are offering  lessons at a beginner or at higher level. If these are oversubscribed, IMPRS may reimburse the costs of a provate language school. For details, contact the IMPRS office.

Registration at the respective University Bonn or Cologne

We expect all PhD candidates to be enrolled as a PhD student at his or her respective university during the time spent for their thesis work.


You might be expected to teach during your PhD. This is part of your general training as a PhD candidate.

Thesis Advisory Committee

The Thesis Advisory Committee, TAC, (consisting as a minimum of your day to day advisor, your official supervisor, a member external to your group)  is meant to advise on academic and other matters, and is expected to meet once every semester.  The TAC also gives recommendation to proceed with the work after the probationary period, and to extend the research contract beyond 3 years if necessary.

Setting up the TAC: Adviser and student have the joined responsibility on both (a) setting up the TAC and (b) its regular meetings. While the executive responsibility to form the  TAC goes to Adviser, (b) the student is responsible to schedule the regular TAC meetings.

PhD Proposal

Each IMPRS student is required to write and submit a PhD proposal (approximately 2-3 pages) within the first 6 months after they have started their PhD. The PhD proposal  is written together with the supervisor. It describes the research objectives to be reached as well as the milestones of the research. The PhD proposal shall  ensure  that the thesis can be successfully finished within the foreseen time frame of three years. In its first meeting, the TAC decides on the viability of the project and recommends, or not, a continuation of the thesis work. In subsequent TAC meetings, updated versions of the PhD proposal may serve as a basis for deciding on the best strategy for a successful completion of the work.


A weekly seminar from students to students gives an overview of all research projects carried out by the members of the school and provides opportunities for discussion between students and researchers. The seminar takes place on Mondays from 13:00 until 14:00 or is organized as a half day seminar.

Every student should give at least one seminar talk per year (length: 20-30 min). Contact the IMPRS office to schedule those talks (approximately in months 6, 18 and 30 from starting your work. In this talk the research project, its progress and aims should be presented

Things to do When Leaving

  • Give written notice of leaving to your landlord (usually 3 months in advance, best by registered mail).  Arrange a time with the landlord to come  checkoff damaged and then pay your deposit back to you.
  • End health insurance.
  • Close electricity and internet account (for which you will normally have given direct debit authorization).
  • Unregister at the Einwohnermeldeamt
  • Terminate any standing orders with your bank (e.g. for rent) in time and finally close bank account.
  • Leave your future address in the IMPRS Office
  • Give a copy of your PhD thesis in digital form (PostScript or PDF) to the IMPRS Office (not necessary if you submitted an electronic version to the eLibrary of the University of Bonn (ULB) or Cologne (KUPS)).
  • MPIfR: “work off” the Laufzettel/Circular letter (i.e. return keys, transponder, return books to the library, pay outstanding bills etc.

1. Acceptance as a PhD candidate

To be accepted as a PhD candidate in astronomy at the University of Bonn, a German Diploma in Physics, a Master of Science degree (including a written Master’s thesis) or an equivalent foreign degree is required. The following information just serves as an information guideline and is therefore not legally binding.

For all binding information concerning the admission please check out:

The following is needed for the application process:

1. Application form

2. Legalized copies of your original documents (titles + transcripts)

3. Proof of English language proficiency (detailed description of your language skills by your advisor if your Msc was not in English language)

4. Copy of residence permit if you are not from the EU (showing the purpose of your stay)

5. Survey form for statistics

6. Letter to dean (copy provided by fellow student)

When you submit your application please make sure that they are orderly presented and put in the right chronological order. Please submit all your documents to the Fachgruppe Physik/Astronomie.

2. Registration at the University of Bonn as a student

Once you have the acceptance as a PhD student “Promotionsbestätigung”, please register as a student online and follow the instructions:

3. Submission of your thesis at the U. of Bonn

Generally, all four members of the examination board need to be qualified as professors (“habilitiert”) one of them can be from outside the U of Bonn. Exceptional cases such as members of the commission are professors from outside Germany are subject to the dean’s approval. Moreover, the dean’s office evaluates each case individually and specific questions should be addressed to  Each PhD candidate has to write to this email address to get a form that he/she needs to fill out before submitting the thesis.

The PhD Examination Board (“Promotionskommission”) consists of 4 members, the 1st referee (the official supervisor), the 2nd referee (second examiner) (who in general is the chairperson of the examination board), a university teacher  of the same or similar field (i.e. a physicist) (in general suggested by the PhD candidate and who must be qualified as a professor (“habilitiert”), and a university teacher external to your subject (meteorology, chemistry or geodesy might be considered too near by the dean, but e.g. pharmacists, biologists or even philosophers are accepted).

Period of Display (“Auslegefrist”): Upon submission of the thesis and all relevant documents (see next page), a complicated procedure follows to collect the reports in the dean’s office and to derive the grade. Then follows a 2 weeks’ term of display plus another week to announce the colloquium.

Note: the grade “excellent” (ausgezeichnet, summa cum laude)  requires a third, external report. The supervisor suggests three referees of which the dean then chooses one. Choosing the external referee and waiting for her/his report may delay the process another 2 months.

The following information is only meant as a rough guideline and is only meant as a service to you.Submit the following to the Promotionsbüro (PhD Office): Mr. Jorg Wenniges, Wegelerstr. 10, Telephone:  0228-73 2232, Opening hours of the office:  10:00-12:00 Monday – Thursday

  • An application to be admitted to the PhD examination procedure. This form can be requested by email at as mentioned before. The form that is published on pages 44 ff. is just a SAMPLE. The application has to be signed and a photo should be pasted in. You have to add a declaration instead of an oath that you have indicated all means of help. This is called “eidesstattliche Erklärung” in German.
  • 5 copies of the thesis – indelibly printed and bound – containing a summary and a curriculum vitae. The layout of the title page and of the 2nd page should follow the example on the reverse page of the details of the examination procedure (“Hinweise zum Promotionsverfahren – attachment 2)
  • If applicable, 5 copies each of advance publications of major parts of the thesis.
  • One single copy of the summary of the thesis (including your name and the title of the thesis – see example attachment 3)
  • One single copy of the curriculum vitae
  • Completed undergraduate and postgraduate certificates (diploma or bsc and msc copies and originals)
  • A “Führungszeugnis für Behörden” (clearance certificate/certificate of no criminal record) – see separate page for details how and where to apply for it (will be sent to the Promotionsbüro directly)
  • A legalized copy of a valid passport and presentation of the original
  • Proof of at least 2 terms doctoral studies at the University of Bonn or an existing employment at the University of Bonn (proof of MPI employment is not accepted)

One copy of the thesis (the examination copy) is stamped and forwarded to the supervisor (1st or 2nd referee) who signs and returns it to the Promotionsbüro. The first and second referees receive the thesis for assessment. The first and second referees submit their assessment to the Promotionsbüro. According to the PhD Regulations they have to do this within one month after request by the Promotionsbüro, i.e. not necessarily one month after submitting. Copies of the assessments are sent to the 3rd  and 4th member of the examination board who have 2 weeks to forward their vote to the chairperson of the examination board (usually the 2nd referee). The chairperson of the examination board informs the Promotionsbüro of the acceptance of the thesis and the cumulative grade. The Promotionsbüro distributes the announcements. And only now the 21 days’ term of display plus 7 days for the announcement of the colloquium (Promotionskolloquium) starts.

Even under ideal conditions (i.e. the referees submit their assessments right away and not take the full time at their disposal), the period of time between submitting and defending the thesis will be at least 2 months! To ensure a smooth and swift process, it is advisable to talk to the 1st and 2nd referee of your thesis as early as possible and also let them have a version of the thesis prior to the official one they are going to get from the Promotionsbüro.  Please note that in general no exams will be possible during the semester holidays!

Conferral of a doctorate consists of two parts:

1. The PhD Thesis: The thesis has to be scientifically substantial and has to document the ability of independent research and adequate presentation of the results. The thesis is normally written in English. It has to be submitted indelibly printed and bound. It must include a complete list of the literature and other sources used and quotations of help received and facilities employed.

2. Oral Exams, consisting of: A public scientific talk with discussion (Promotionskolloquium) and a non-public oral exam (Disputation) following the talk. In the Promotionskolloquium the doctoral candidate presents the scientific results of his/ her PhD work. The length of the talk should not exceed 30 minutes. Afterwards 15 minutes should be allowed for scientific discussion. Be aware that part of the audience (including part of the examination board) are not experts in your field. The Disputation will take between 30 minutes and 90 minutes. A sealed envelope (containing the reports and grades) that you will be given after the defence. needs to be submitted to the Promotionsbüro.

Based on this you will receive a certificate that you passed the PhD exam. The official certificate (“Promotionsurkunde”), however, will only be delivered after submitting the following documents:

  • Confirmation by the institute’s (= Astronomical Institutes’) librarian (Mrs. E. Danne, room 3.09 Uni) that one copy of the thesis has been handed over (attachment 4)
  • “Entlastungsbescheinigung” (relief) by the institute (attachment 5)
  • Proof that the thesis has been made available to the scientific public.

Either a confirmation of the supervisor that essential parts of the thesis have been or will be published in a journal or that the thesis will be distributed by a commercial publisher with a minimum circulation of 150 copies (attachment 6).

Or, if the thesis will be published for the first time, approval by the supervisor to one of three forms of publication (see attachment 7). We encourage you to submit an electronic version to the eLibrary of the Universitäts- und Landesbibliothek Bonn (UBL). For the procedure, please check out

Prior to printing please get in touch with concerning the requirements for the print-outs.

Führungszeugnis für Behörden (certificate of criminal history): Application has to be made at the Bürgeramt of your place of residence (e.g. Bürgeramt Bonn: Stadthaus, Berliner Platz 2; Bürgeramt Bad Godesberg:  Kurfürstenallee 2-3; Bürgeramt Beuel:  Rathaus Beuel, Friedrich-Breuer-Str. 65; Bürgeramt Hardtberg:   Villemombler Str. 1 (Opening hours:    Monday and Thursday:   8:00 – 18:00, Tuesday, Wednesday and Friday:  8:00 – 13:00)

Apply for the Führungszeugnis in person bringing your passport. In principle it is possible to just go there and ask for it, but if you don’t speak (enough) German it is recommended to take a filled-in but unsigned application form (“Antrag auf Ausstellung eines Führungszeugnisses”) with you. You should sign it in the presence of the clerk and pay a fee. The document, which is valid for 3 months, will be sent  directly to the Promotionsbüro.

City of Bonn, information in english:

Enrolling at the University of Cologne

Documents required for admission

Application for admission

Application for admissiona as a doctoral student

The address for submission is: Universität zu Köln, Akademisches Auslandsamt, SSC Studierenden Service Center, Universitätsstr. 22 a, 50923 Köln, Mrs. J. Soucek, Email:, Phone: 0221 – 470-1392; Office hours: Tuesday 10:00 – 12:00,  Wednesday 16:00 – 18:00.

As soon as the PhD examination board of the Faculty of Mathematics and Natural Sciences has given their approval, you will receive admission to study Physics (“Zulassung zum Studium”) at the University of Cologne. This will be initially limited to 2 semesters (so-called preparation for a PhD – “Promotionsvorbereitung”). At the same time you will also receive the registration form and details.

The International Office forwards your request for recognition of your foreign degree(s) to the PhD examination board of the Faculty of Mathematics and Natural Sciences. Due to the high number of doctoral candidates, this process may take between several months and one year to complete (hence the initial enrolment for 2 preparation semesters).

You will finally receive a letter of admission to the PhD examination procedure at the Faculty of Mathematics and Natural Sciences. Along with this letter a stamped and signed copy of the form „Mitteilung der Promotionsabsicht“ is returned. Please keep this safe! You will need it again when you submit your thesis.

Please note that the second referee can be a professor appointed for lifetime from another university if the first referee is a professor for lifetime at the University of.


IMPRS PhD researchers are required to be enrolled during their studies at one of the partner universities.

The above-mentioned admission notification will mention the date by which you have to mail (Akademisches Auslandsamt der Universität zu Köln, Albertus-Magnus-Platz, 50923 Köln) or submit personally (address and opening hours as in previous chapter) the following documents: Completed registration form („Antrag auf Einschreibung“) and a Certificate by your medical insurance company

There are no tuition fee, but you have to pay a registration fee of about 284 Euro per semester, which entitles you to free public transportation in the region of NRW and reduced event tickets. Upon receipt of the above mentioned documents the International Office will send you a preliminary Semester Ticket and a pre-filled money transfer form for the payment of the semester fee (“Sozialbeitrag” ) which currently amounts to about 284 € for each semester. The Semester Ticket and the money transfer form will also state your student ID number (Matrikel-Nummer).

Student ID

Approximately 4 weeks after you have paid the social contribution, your matriculation documents and the final student ID card will be sent to you along with the transfer form for the next semester’s fee (see “Re-Registration” below).

Together with a photo ID the student ID can be used as a ticket for busses, trams and local trains within NRW free of charge. This ticket is valid for 6 months (starting 1st October or 1st April, respectively), i.e. not only during lecture periods. With the student ID card you also can get a students’ reduction  on tickets for theatres, concerts, museums, etc.


Once enrolled at the University of Cologne, you will have to re-register (“Rückmeldung”) for each of the following semesters. There is a registration deadline by which you need to transfer the registration fee (“Sozialbeitrag”) — 15 July for the winter term and 15 February for the summer term. You will then receive your semester documents automatically. Please take into account that the transfer could take several days! If the deadline is missed a fine has to be paid.

Change of Address

Please inform the academic exchange office (“Akademisches Auslandsamt”) about all changes of your personal data (i.e. change of name, address, nationality) immediately, quoting your registration number (Matrikelnummer).

Submission of thesis at the U of Cologne

Submission Procedure:

For the submission procedure and everything related to that including all necessary documents please check out:


IMPRS travel funding

IMPRS can financially  contribute to facilitating equal opportunities, conferences, workshops or of you want to visit or invite scientific collaborators. In general, IMPRS does not finance the “core business” of your research group, e.g.  consortium meetings or regular observing trips. If the travel cost exceeds 1000 Euro, you need to seek for additional funding, e.g. from the organiser of a conference (e.g. a waiver for the conference fee or a contribution to the lodging costs) or from the Bonn Cologne Graduate School (BCGS).

Before requesting IMPRS or MPIfR funding for the fist time, you need to see Ms. Mertens  of the MPIfR administration (room 1.05, phone 0228 525235, smertens at to fill out a form with your bank data, frequent flyer numbers etc. to ensure a fast reimbursement of your costs.

You can ask for IMPRS funding (e.g. travel, lodging, per diem, conference fees, child care) using the  IMPRS form “Funding Request”. The application should be made 6 weeks ahead of the travel date, respectively any deadlines there may be for registration or pre-payment. Have the MPI form “Dienstreiseantrag” signed by your director or in case you are from a partner university by Prof. Zensus. Any flight and train tickets  funded by IMPRS or the MPIfR have to be booked by the directors’ secretaries or the administrative officer in charge (Mrs. S. Mertens).

If you need to rent a car or use your own car, this needs approval by an MPIfR director and should be mentioned in the “Reise- und Dienstreiseantrag”. Hotels can be booked and in certain case prepaid by the MPIfR group secretaries or by Ms. Mertens to make sure that the hotel costs comply with MPG rules. Any hotel bills should be issued to the MPI für Radioastronomie and mention your name. In general you need to prepay any conference fees, in particular for events outside the EU. If you do that with your credit card, you can immediately ask for a refund from the MPIfR administration presenting the proof of payment. If that is not an option for you, please discuss with Ms. Mertens whether a wireless transfer can be made.  The cost for a conference dinner will only be refunded if approved by an MPIfR director. The use of a taxi is refundable only under certain conditions (e.g. no public transportation). Costs for necessary visa, including travel to the consulate, can also be reimbursed as well as costs for necessary vaccinations. However, the costs for additional travel health insurance (recommended for travel outside the EU, cost: about 20 Euro/ year) and luggage insurance cannot be claimed.

You can request an advance payment of 80% of your travel costs if these are more than 200 Euros (in the MPI “Dienstreiseantrag” tick the box “Ich bitte um einen Vorschuss”. If you are granted financial support by a conference organizer or e.g. from BCGS, this has to be entered on the application form (“Zuschüsse von 3. Seite” / grants by 3. party).

Important: If you want to extend your travel for private reasons by more than 5 business days, you have to pay the entire costs for the flight/ train yourself. If you extend a travel for private reasons and this makes the travel more expensive, you have to pay the difference. This makes it worthwhile to discuss any private extension with your group secretary or Ms. Mertens.

Fill out and hand in the form Reisekostenabrechung to Ms Mertens, carefully reading the instructions, within 4 weeks after your travel. Attach all receipts. Note: you do not have to collect receipts for meals as you will be paid a lump sum.

Affiliation and Publications

In publications the IMPRS, membership should be indicated as a footnote to the name (“\thanks{…} for most journals). The following text should be used: Member of the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne.

PhD researchers who received IMPRS funding (e.g. a research contract or travel funding) should indicate this in the “Acknowledgements”: NN received financial support for this research from the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne

For IMPRS researchers with MPIfR or IMPRS funded research contract: In order to ensure the quality of the MPIfR publications, all publications (including theses and conference proceedings) require an internal referee process and the approval by a director. Before publishing your research, make sure whether  any publication costs will be covered by your group. The internal referee system can be accessed via the intranet page

Your “Buddy”

New IMPRS researchers will be assigned by our IMPRS office or by their group a “buddy”, i.e. an experienced IMRPS researcher who can give advice about life in Germany and at the partner institutes.

Student Speakers

The Student Speakers are the representative of all IMPRS students. There is one representative from each affiliated institute, i.e. one from the MPI, one from the AIfA and one from the University of Cologne. One, external, representative also participates in the annual MPG PhD Network meeting.

In case of conflicts

Don’t be shy to discuss any problems or conflicts with your supervisors. In many cases, a solution can be found. Your Thesis Advisory Committee is also an excellent forum to address any concerns.

If you feel you have a conflict with your supervisor or another coworker that you cannot solve by yourself, the MPIfR mediator can help. Unfortunately this position is vacant right now. If you wish so, this advice would be anonymous.

Dr. Simone Pott is the institute’s gender equality officer and would be glad to guide you in any gender related issues.

If you have a conflict or question regarding research ethics, you can address this to the ombudsperson, elected by all scientific staff at the MPIfR, Dr. Friedrich Wyrowski

The Betriebsrat (works council) is an elected body that defends the interests of the employers at the MPIfR and the partner universities.

A comprehensive list of contact points, internal and external of the MPIfR can be found here. The partner universities/ institutes may have their own structures.

If you are feeling down…

To live in a foreign country can be an enriching experience but it can also lead to frustration and anger. To adapt to a new (research) environment is a challenge that requires a high level of frustration tolerance. You might miss your home country and your friends and family. If, however, you experience a severe change in your mood that does not improve over the course of several weeks you might consider seeing a health expert. A basic point of contact in Germany is a general medical doctor or in German “Allgemeinmediziner”. She or he might then give you advice on whether you need the help of a specialist.

The MPIfR has an agreement with pme Familienservice, a company that provides free and anonymous short-term counseling by professional social workers or psychologists. If you have any personal issues, health/mental health issues or job related issue that worries you, just dial 0800 801007070 and mention that you are employed by the Max Planck Society (also in case your are in the IMPRS but at one of the partner universities).

If you are in a severe crisis, you can also directly contact the nearest psychiatric clinic. In Bonn, this is the LVR Klinik (Kaiser-Karl-Ring 20, 53111 Bonn, phone 0228 551-1), and in Cologne the Universitätsklinik (Kerpener Str. 62, 50937 Köln, phone: 0221 478-0)

Medical emergencies

In case of a medical emergency you should, if possible, first see your medical doctor (Allgemeinmediziner) mentioning the urgency. He or she can refer you to a specialist if required. If it is a work related accident or illness, you should mention it at the doctor’s reception desk. Outside doctors’ consultation hours, call 116117 and you will be told where you find the nearest emergency center. In case of a life threatening  emergency, do not hesitate to call 112 for an ambulance.

Support for Families

Researchers with young families are supported by the MPI and the partner universities in a number of different ways. They can apply for a babysitter subsidy from the Max-Planck-Society (ask our human resources department for more information).  MPI employees can use the services of the PME Familiy Service, who can e.g. nadvice you on finding child care. If you want to use their services, see our human resources department and get a voucher. The MPI and the partner universities also have reserved places in nearby day cares. You can use the “parent child offices” available at the MPIfR and at AIfA and work while taking care of your child. Moreover, help can be provided when applying for the state granted child subsidy the so-called “Kindergeld”.

Title Link
IMPRS logo: version for light background here
IMPRS logo: version for dark background here
Thesis Advisory Committee (TAC) meeting report (to be filled out by your supervisor) here
PhD Proposal Model Form (to be prepared by the student and his/ her advisor) here
IMPRS Funding Request here 
IMPRS Monthly Seminar Feedback Form here
MPIfR: Relevant Forms
MPI Travel Request (Dienstreiseantrag) here
Form to claim travel expenses here
Vacation request form here
University of Bonn: Relevant Forms
Application for admission to doctoral studies (in English – read only) here
Details on application for certificate of criminal history/clearance certificate (Polizeiliches Führungszeugnis) here
Example for application for certificate of criminal history/clearance certificate (Polizeiliches Führungszeugnis) here
PhD Rules and Guidelines (Promotionsordnung) here
PhD Rules and Guidelines (English translation) here
University of Cologne: Relevant  Forms 
Application form for admission to studies for foreign applicants here
Information on the PhD process here