If you wish you to carry out a postgraduate degree (whether a M.Sc. or a Ph.D.) at CBPF you must pass the Unified Examination for the Graduate Degrees in Physics in Rio de Janeiro, UNIPOSRIO-FÍSICA. This is a selection process which entails a written exam and an interview. There are proceedings already in place that enable a potential student to go through this selection process in English and from outside Brazil, without the need for him/her to travel over to Brazil for it. For further information on the UNIPOSRIO selection process you may see here. Depending on the results in the selection process, a potential student may be allowed to undertake the postraduate degree and may be also granted a studentship for it. There are two entries a year for a postgraduate degree, one in March and one in August, with the corresponding UNIPOSRIO selection process taking place a few months before the start of the degree. The studentship for the M.Sc. is for 2 years and for the Ph.D. is for 4 years. The next call will probably have a registration deadline of May 2018, for a start of the postgraduate degree in August 2018. For further information on the postgraduate degrees at CBPF you may see here.

There is the following excellent alternative which does not involve going through the UNIPOSRIO selection process:

PPGCosmo

This is a new international Ph.D. program on Astrophysics, Cosmology and Gravitation. The student would have one supervisor from a Brazilian institution and one co-supervisor from a non-Brazilian institution. The possible Brazilian institutions are: CBPF, Federal University of Espírito Santo (UFES), UFBA and UFJF; the possible non-Brazilian institutions are: Fermilab (U.S.A.), ICG-University of Portsmouth (U.K.), Cote d'Azur Observatory (France) and ITP-Heidelberg University (Germany). The student would spend about 1 year in the non-Brazilian institution and the rest of the time in Brazilian institutions. The Ph.D. is awarded by UFES (although the student may have a supervisor and a co-supervisor none of which are from UFES) and the program is funded by the Brazilian agency CAPES. The deadline for applications is February 5, 2018, for the Ph.D. to start in March 2018. For further details, please see here.

There are also the following funding possibilities for postgraduate degrees.

Sandwich Doctorate scholarship

This is part of the new program 'Science Without Borders', which is the result of the joint effort of two different Brazilian agencies, CAPES and CNPq. This scholarship is intended for students registered for a Ph.D. in a Brazilian insitution who wish to carry out part of their Ph.D. in a non-Brazilian institution. The duration of this scholarship is between 3 and 12 months. For further information you may see here.

CNPq

These scholarships are awarded by the Brazilian agency CNPq. The scholarship for the masters is for a duration of 2 years and for the Ph.D. is 4 (exceptionally 5) years. For further information you may see Sec.4 in here (in Portuguese).

TWAS-CNPq

This program is a joint collaboration between the Brazilian agency CNPq and the The World Academy of Sciences (TWAS). They offer Ph.D. Fellowships to students from developing countries (other than Brazil) to do a Ph.D. for a period up to 4 years. The Ph.D. can be carried out either in its totality in a Brazilian institution (full-time Ph.D.) or else partly in a Brazilian institution and partly in a non-Brazilian institution (sandwich Ph.D.). The next call for CNPq-TWAS is meant to come out some time soon during 2018. For further information you may see here, here (full-time Ph.D.) or here (sandwich Ph.D.).

IRAP Ph.D. CAPES-ICRANet

This is a program of the International Center for Relativistic Astrophysics Network (ICRANet) joint with the Brazilian agency CAPES. The fellowships are for 3 years with the final Ph.D. degree jointly delivered by the academic institutions participating in the program. Every year, the start date of the appointment is at the beginning of September and the deadline for the application is August 20th. For further information on this program and other Ph.D. possibilities, you may see here.

Faperj

This funding is from the agency FAPERJ, of the state of Rio de Janeiro. This scholarship is intended for students registered for a Ph.D. in a Brazilian insitution who wish to carry out part of their Ph.D. in a non-Brazilian institution. The duration of this scholarship is between 4 and 12 months. For further information in Portuguese you may see: Secs.IV and V of "Bolsas" in here for the funding details and in here for a calendar of call deadlines.

CNPq-CLAF

This program is a joint collaboration between the Brazilian agency CNPq and the Centro Latino-Americano de Física (CLAF). This program is open only to nationals of a Latin-American country (except Brazil) who wish to carry out a Ph.D. in Physics in a Brazilian institution. This year's call has not been announced yet - any upcoming calls will be announced in Portuguese or Spanish in here.