By a strange mistake you have reached the
Mayagüez
Pulsar Pages
Please
go somewhere else, this site is boring...
If
you want to stay here, it's your own decision...
Because of space limitation, most of the pulsar graphs and pictures of this web site are located on a different server, which is now unavailable. I'm sorry for the inconvenience. To solve this problem, I will remodel this web site, hopefully before the end of 2004. I'm sorry, I have a lot of other work now.
Interested in seeing the International
Space Station in the sky?
Click here
|
- 8 April 2001: one page with intensity bins for PSR 0540+23
- 12 April 2001: 17 pages of single pulses of PSR 0540+23
- 13 April 2001: one page with intensity bins for PSR 1541+09.
- 15 April 2001: 16 pages of single pulses of PSR 1541+09
- 15 April 2001: one page with intensity bins for PSR 0611+22
- 15 April 2001: 12 pages with single pulses of PSR 0611+22
- 16 April 2001: one page with intensity bins of PSR 1133+16
- 19 April 2001: 7 pages with single pulses of PSR 1133+16 (S)
- 20 April 2001: 13 pages with single pulses of PSR 1133+16 (N)
- 30 April 2001: 4 pages of single pulses of a certain pulsar
- 30 April 2001: 1 page with intensity bins for a certain pulsar
There will be some recent news here in a few days, about very interesting things that we (i.e. myself, Ramesh Bhat (MIT), and Dunc Lorimer (Jodrell Bank)) have found in one of the pulsars. Please come back in a few days (around 20 November, 2002).
Have a look at these pages - if you have difficulty to sleep, looking at these pages is much more effective than counting sheep.
At this moment this website has more than 100 pages - I'm trying to make navigation between those pages as simple as possible. If it's not as simple as I think, I apologize for that. Please scroll down this page, click on links on this page, and use the navigation bar on the left.Short description of ASTR 4005
Description of the SETI@home program
updated November 14, 2002
This site is (and will be) under construction. It is devoted to some aspects of pulsar research but you can also find here some other (I hope interesting) things.
Please use at least version 4 of the Internet Explorer - Netscape users are out of luck - formatting in Netscape practically doesn't work. Sorry about that...
Some elements of this site
were last updated on November 14, 2002, 22:30 AST 
Pulsars - beware! These three ladies are looking into your private lives...
... and they would go through all your
papers like a tornado...
I took that picture in
Mayaguez in September 1999
Other pictures from the conference in Ponce
...so I have time to take part in a TV
program for PBS...
click on the picture above to see more pictures from that evening
Pulsar Manual - How to Observe Radio Pulsars
using
The Arecibo Radio Telescope
Some pictures from the 197th AAS Meeting
in San Diego, California (7-11 January 2001)
Click on the picture below to see some 30 more pictures
Pictures are located on a
different server which is sometimes down. If you can't see those
pictures, try again later.
Pictures
from IAU Colloquium No. 177
"Pulsar
Astronomy - 2000 and Beyond"
Bonn,
Germany, 30 August - 3 September 1999
updated
June 5, 2000
Some night pictures of our Campus - updated 2 Sept. 2000
Some more night pictures of our Campus - updated 6 Sept. 2000
Click
here for the SETI home page (opens a new browser window)
During the hurricane season click here
for the latest information.
Twinkling of visible stars is caused by density fluctuations in the Earth's atmosphere. These density irregularities result from thermal and other motions of the air along the line of sight in the atmosphere of the Earth. Time scale of these changes is short, hence twinkling of the stars is rapid.
In 1967 in Cambridge, England, Professor Anthony Hewish and his graduate student, Jocelyn Bell Burnell, were studying a similar phenomenon at longer wavelengths, using a radio telescope specially developed for this project. The question was, whether compact radio sources would exhibit similar twinkling, caused by density fluctuations in the interplanetary plasma (the solar wind) and in the interstellar medium. Almost immediately, weak, precisely periodic radio pulses were detected.
Explanations of the phenomenon as man-made signals transmitted from space probes or reflected from the Moon or planets were quickly ruled out. Since the duration of the pulses was of the order of 20 ms, implying that the source of the signals could not be larger than the Earth, a possibility of involvement of an extraterrestrial civilization was also (briefly) considered.
Soon after that three more similar pulsating sources were detected, with different periodicities, and it became clear that the sources had to be natural phenomena. They were named "pulsars" and the problem of understanding what and why is pulsating appeared.
Three mechanisms were considered as possibilities for producing the periodic signals:
Radial pulsations (like those in classical Cepheids). Observed periodicities were too fast for pulsations of white dwarfs, and much too slow for neutron stars. Discovery of the Vela and Crab pulsars, both with periods shorter than 0.1 s, ruled out that possibility, since theoretical models did not predict periods shorter than 1 second;
- Orbiting white dwarfs or neutron stars. That model was ruled out because even a pair in contact would have an orbital period not less than about 1.7 s. Apart from that, in such a system the period should decrease (because of energy loss in the form of gravitational radiation), while the observations showed clearly that pulsar periods were (very) slowly increasing;
- Rotation of a very small but massive object. Rotating white dwarfs would not survive periods shorter than about one second (because of centrifugal forces). The only possibility was the rapidly rotating neutron star. Formation of such stars in a gravitational collapse of what remains from a supernova explosion was predicted theoretically 33 years before the first pulsar was discovered. Association of the Crab and Vela pulsars with visible supernova remnants gave a strong support to interpretation of pulsars as rotating neutron stars created shortly after supernova explosions.
Today the number of known radio pulsars is more than a thousand. While the amount of the observational material is growing daily, the number of still unanswered questions is not decreasing. Some of these questions have been answered, but also new questions have been asked at the
IAU
Colloquium No. 177
"Pulsar
Astronomy - 2000 and Beyond"
Bonn,
Germany, 30 August - 3 September 1999
Some time ago there was a
Workshop
on the Relationship Between
Neutron
Stars and Supernova Remnants
June
1-4, 1998
Marciana
Marina, Elba Island (Italy)
The most important groups working in Pulsar Research
If you want to read the Pulsar Newsletter (a bit outdated),
click this:
This is the place where you can hear how
pulsars pulse. Click this: 
It may take a while to load but it's worth it! Try all three pulsars to hear the difference between different pulsar periods (needs a soundboard).
A Tutorial on Radio Pulsars (Jodrell Bank, UK)
European Pulsar Network (EPN)
"Binary
and Millisecond Pulsars" - a review article by D.R. Lorimer
Max-Planck-Institut für Radioastronomie,
Bonn, Germany
An interactive list of my publications is here.
Come back later if you are interested in radio pulsars. There will be more soon.
Interested in seeing the International Space Station in the sky? Click here, wait until the entire applet loads, then select the city closest to you in the right-hand panel (for Puerto Rico select San Juan).
- Pressing "Next Pass" will show a table of several dates and times when the ISS will be flying above you (table lists all events, also during the day).
- Pressing "Next Sighting" will list only those cases when the ISS can be actually seen (after sunset or before sunrise).
- Pressing "Sky Track" will show a map (interactive) of a portion of the sky, with constellations and the track of the ISS indicated.
- You can also press "Print" to make a printout.This link will open a new browser window. To come back to this web site, close that new window.
A little bit about Astronomy
And a little bit about Radio Astronomy
A
Multimedia Tour of the Solar System (by Bill Arnett) - Fantastic!
(opens in a new browser window)
Electronic
Publications for Astronomers
Read an article from "Sky and Telescope"
The
Leonids: King of The Meteor Showers
This meteor shower was expected on November
17, 1998 - arrived one day earlier
updated
23 August, 2002
Important
information about Astronomy
Courses for
the academic year
2002-2003
We have joined (on May 17, 1999) the SETI@home project. 14 PC's in the Physics Department, plus mine at home, are processing data from the Arecibo Radio Telescope.
Read about SETI: Searching for life
(will open a new browser window)Read about SETI: The Radio Search
(will open a new browser window)Read an article from Sky and Telescope about SETI
(will open a new browser window)Click on the icon below to see the current statistics for Puerto Rico. The username for all our computers is Leszek.
Some faculty members and some students, who participate in the SETI project, form a group. You can see the listing of the group together with the current statistics of the group and all its members here.
There is also a table that shows the top 200 university teams. Check our position there (look for Recinto Universitario de Mayagüez). On September 27, 1999, we were at the 100th place (a drop from 63rd place that we had in July, 1999). Our position now (12 November, 2002) is 92 (up two places since last year).
General statistical information about progress of SETI is here.
Calculators,
Computer Magazines, Faster Modem Connection
Flash
upgrades for TI-92 Plus and TI-89 are already available! Go to the
Student Pages for the details
The picture below shows the new 32 meter radio telescope that belongs to the Torun Centre for Astronomy (TCfA), which is a part of the Nicholas Copernicus University, Torun, Poland. This instrument is used for VLBI and pulsar observations. If you look carefully, you can see me in this group of radio astronomers. Note, that the telescope is more than half a mile behind this group of people.
Here you can send me an e-mail 
And here you have a lot for the spirit...
I hope your PC will not do this 
while you are reading these pages.
Counter was reset on April 1, 1998
and on June 18, 1999