The proposal season has started and I've been just trying to improve my last year one. I've been just reading plenty of new papers on high redshift universe... at the end it will be just one sentence in the proposal text.
I submitted the revised version of the radio galaxy paper. It took some time to rework the referee's comments. In particular the one about the choice of the model for the emission of the hot gas. APEC is the standard thermal emission model from a collisional plasma in equilibrium, but it has a strong dependence on the metals. Our source has small number of counts and getting any reasonable constraints on the metals and temperature is not really possible... but I rerun the model and list the new parameters.
The results of the paper are nice and hopefully the referee will be o.k. with the revisions.
It is snowing tonight and I'm missing a dinner with Lukasz, Teddy, Malgosia and Giulia. Lukasz has just arrived and we hope to work for the next two weeks on random projects. Teddy is here just for two days
for discussion and support on the big chandra project. Anyway, will go out tomorrow when the snow stops..
Feb. 16, 2012
This was a day filled with meetings... We had our group lunch with Tom Loredo with interesting discussion of stats project the students are working on. One of the ideas that came up during the meeting was to think about the ways to publish the full likelihood information with the data. This information could be published as part of on-line data available in ADS. However, how could we represent such information and how to make sure that people would do it? We may need to come up with some examples.
I had a discussion with Alyssa and Vinay on addition of astrostatistics course to the astronomy graduate students program at HU. Vinay and I wrote a short bullet summary of possibly syllabus. After talking with Alyssa we came up with some options that she will discuss at the curriculum review meeting. Important timing as this is apparently the course revision which it is going to affect the next decade. Hopefully we'll get some astrostat there. The students do not know what they are missing now, so it is hard to know how many of them would be interested in such a course.
I stopped by the SolStat workshop this afternoon to see Alex describing the conceptual difference between the likelihood and a posterior probability. Important distinction that requires shift in the ways one think about the data and probabilities.
P(theta | Y) = P ( Y| theta) * P(theta) / P(Y)
where for parameters theta P( Y | theta) represents the likelihood of observing data Y... while
P(theta | Y) represents the full posterior probability of the theta given that we observed Y.
P(theta) represents the prior.
Alex talk made me think about it again...
Attended a great CfA colloquium today on the spiral arms in the Galaxy! One of the best talks I've attended recently. The observations are made in CO and given the velocity shifts one gets a 3D data that can provide the information about the molecular clouds location in the Milky Way. The tricky observations of the far side of the galaxy and modeling of the data shows that there is a bar at 3kpc and also a far arm, a possible extension to the Centaurus arm on the far side. Great talk and the data!
Malgosia has finished several plots of the lightcurves overplotted with the rms, and rms histograms. Now it is time for interpretation and possible connections to the supermassive BH.... fun work which requires some thinking.
Yesterday... I talked with Tracy during lunch. Interesting idea about the RM and the X-ray clusters of galaxies - the cool cores with radio sources display higher RM.
I had a discussion with Alyssa and Vinay on addition of astrostatistics course to the astronomy graduate students program at HU. Vinay and I wrote a short bullet summary of possibly syllabus. After talking with Alyssa we came up with some options that she will discuss at the curriculum review meeting. Important timing as this is apparently the course revision which it is going to affect the next decade. Hopefully we'll get some astrostat there. The students do not know what they are missing now, so it is hard to know how many of them would be interested in such a course.
I stopped by the SolStat workshop this afternoon to see Alex describing the conceptual difference between the likelihood and a posterior probability. Important distinction that requires shift in the ways one think about the data and probabilities.
P(theta | Y) = P ( Y| theta) * P(theta) / P(Y)
where for parameters theta P( Y | theta) represents the likelihood of observing data Y... while
P(theta | Y) represents the full posterior probability of the theta given that we observed Y.
P(theta) represents the prior.
Alex talk made me think about it again...
Attended a great CfA colloquium today on the spiral arms in the Galaxy! One of the best talks I've attended recently. The observations are made in CO and given the velocity shifts one gets a 3D data that can provide the information about the molecular clouds location in the Milky Way. The tricky observations of the far side of the galaxy and modeling of the data shows that there is a bar at 3kpc and also a far arm, a possible extension to the Centaurus arm on the far side. Great talk and the data!
Malgosia has finished several plots of the lightcurves overplotted with the rms, and rms histograms. Now it is time for interpretation and possible connections to the supermassive BH.... fun work which requires some thinking.
Yesterday... I talked with Tracy during lunch. Interesting idea about the RM and the X-ray clusters of galaxies - the cool cores with radio sources display higher RM.
Feb 13, 2012
Working on calculating uncertainty on the flux. Sherpa functions which use simulations to access the uncertainty are not fully developed and in many cases the simulation halts. I have been trying to solve some of the issues in my script, but as of today my final table is still missing the numbers. I plan to try the new pyblocxs runs and see if I can get the set of parameters to use.
Feb.11, 2012
Last week was not as productive as I hoped for. However, I managed to organize the first discussion on strategies for Chandra jets proposal. Need to summarize and circulate notes today... The plan is to focus on the high z science and include the whole sample, but revise strategies to see if there is a more efficient way to accomplish the science goals. Have to work on the science this weekend.
Malgosia started writing up the variability case from Bozena's visit. We still need to understand issues with statistical uncertainty on measured excess variance. Including the standard equation seems to overestimate the error. I was considering the simulations to try to understand the behaviour of this uncertainty.
Giulia is working with the data and will try to use Brandon's radio to gamma-ray relation to place the points on the graph. She is going to present the result of this work in the workshop early March, so we do have to have the results soon.
Still wondering about the HST proposal.. If I get the science case together we might be able to do it before Feb.24 deadline.
Malgosia started writing up the variability case from Bozena's visit. We still need to understand issues with statistical uncertainty on measured excess variance. Including the standard equation seems to overestimate the error. I was considering the simulations to try to understand the behaviour of this uncertainty.
Giulia is working with the data and will try to use Brandon's radio to gamma-ray relation to place the points on the graph. She is going to present the result of this work in the workshop early March, so we do have to have the results soon.
Still wondering about the HST proposal.. If I get the science case together we might be able to do it before Feb.24 deadline.
Feb.7, 2012
Started thinking about Chandra proposals this week. Met with Malgosia and Giulia yesterday to do some brainstorming. Malgosia will focus on the new sample of heavily absorbed AGNs in nearby galaxies,
while Giulia will continue her studies of the Fermi sources. The two projects are quite interesting and hopefully we'll get the observing time.
There is also Magda proposal on the new X-ray cluster that I should start...
The main topic of the discussion this week is a large project of high z radio sources with the jets activity.
We did not get the time last year, but we need to try.
Feb.1, 2012
Bozena is visiting this week and we started analysis of X-ray variability in quasars. Basically downloaded the data and started analysis of the lightcurves. Malgosia is creating the lightcurves and cleaning it.
I just wrote a few lines of python to calculate rms histograms. We need to have the analysis done for our initial discussion today.
Andreas and Vinay initiated a discussion on image analysis yesterday. The old issues of detection of faint extended features, with not clearly defined borders comes back again. This will be some long- term work
and we decided to start involving students. In meantime I should just go back to the data and application of LIRA to my quasar data, but not until after the proposal deadlines on March 15.
Proposals... Started already thinking about project, but the real work starts next week.
Jan.27, 2012
Finally found some time to work on the tables and the text of the paper that I need to send back to the journal after responding to the referee's comments. I did not finish, but updated the numbers in the table and added some more text on the abundances. Need another day to finalize the text and new figures. I made the new figures a couple weeks ago, but did not generate the final plots for the paper.
Marianne asked for a copy of my old review of accretion disks models. I sent her a pdf file, but need to post it on astro-ph finally. Some people are still using it which is great.
Quasar Tea was interesting today. Andy presented his results on silicon absorption in Compton thick Sy2 nearby galaxies. In his carefully selected sample of 20 sources the silicon absorption seems to be related to the dust in the host galaxy, not the torus. High optical depths of the silicon line are seen mainly in the disturbed/merger type galaxies which do show a lot of optical dust features in the images.
Bozena arrived this afternoon. We'll work on quasars variability next week.
Marianne asked for a copy of my old review of accretion disks models. I sent her a pdf file, but need to post it on astro-ph finally. Some people are still using it which is great.
Quasar Tea was interesting today. Andy presented his results on silicon absorption in Compton thick Sy2 nearby galaxies. In his carefully selected sample of 20 sources the silicon absorption seems to be related to the dust in the host galaxy, not the torus. High optical depths of the silicon line are seen mainly in the disturbed/merger type galaxies which do show a lot of optical dust features in the images.
Bozena arrived this afternoon. We'll work on quasars variability next week.
Jan. 26, 2012
Today was the deadline for MERLIN proposals and yesterday I spent time working on the one with Magda. We asked for 4 hours to observed one of our CSS radio sources that is in the core of a bright X-ray cluster. We discovered the cluster in our Chandra observations in Dec.2011. It is exciting, because the compact radio sources are rare in clusters, and this is only the second one known. However, we do not know whether the source is really compact and does not have some large scale radio structure which is invisible in the current radio data. The new data should provide us with a better view and also give spectral information for the structure. Hope we get this approved!
I also went to the morning meeting and talked about Sherpa things. We need to improve the calculations of flux and flux errors. Of course things are working o.k. but the user interface is confusing. Need to spend some time on running the code and figuring out what do we really want here.
Also, yesterday Tom finally started looking back at the background model. We may finalize the model for contrib pages, but it needs testing and documentation, which will take a day*pi.
Meeting with Malgosia and talked about the sample of obscured AGN observed in hard X-rays. Our radio galaxy shows very low scattering fraction indicating the small opening angle of the obscuring "torus". There are several sources similar to ours in the sample. We do need to spend some time on learning about this sample and possibly get better data. It is interesting to think about the Sy2 torus being physically different than Sy1. Sy2 apparently do not show any dependence on the viewing angle and this would indicate departures from the unification model. Interesting!
Giulia selected two targets for the initial analysis of the young radio sources. First she looked at the galaxy but it was a bit confusing for this first step. We decided it is better to start with two quasars, so we know that they could be beamed and detectable by Fermi. Curious to see the results.
I have only a little time to finalize the abundance tables for the paper. All the calculations are done with the code, and the first step in creating a latex table is done in Python, but then the final tweeks to the latex table require manual work which is long. But the table is done. The main result shows the high abundances in the central regions and low everywhere else, which is typical to an elliptical galaxy.
Decided about the big project. We have to study the full sample and start with the optical properties of the sources before selection for Chandra observations. Sent email to the group.
I also went to the morning meeting and talked about Sherpa things. We need to improve the calculations of flux and flux errors. Of course things are working o.k. but the user interface is confusing. Need to spend some time on running the code and figuring out what do we really want here.
Also, yesterday Tom finally started looking back at the background model. We may finalize the model for contrib pages, but it needs testing and documentation, which will take a day*pi.
Meeting with Malgosia and talked about the sample of obscured AGN observed in hard X-rays. Our radio galaxy shows very low scattering fraction indicating the small opening angle of the obscuring "torus". There are several sources similar to ours in the sample. We do need to spend some time on learning about this sample and possibly get better data. It is interesting to think about the Sy2 torus being physically different than Sy1. Sy2 apparently do not show any dependence on the viewing angle and this would indicate departures from the unification model. Interesting!
Giulia selected two targets for the initial analysis of the young radio sources. First she looked at the galaxy but it was a bit confusing for this first step. We decided it is better to start with two quasars, so we know that they could be beamed and detectable by Fermi. Curious to see the results.
I have only a little time to finalize the abundance tables for the paper. All the calculations are done with the code, and the first step in creating a latex table is done in Python, but then the final tweeks to the latex table require manual work which is long. But the table is done. The main result shows the high abundances in the central regions and low everywhere else, which is typical to an elliptical galaxy.
Decided about the big project. We have to study the full sample and start with the optical properties of the sources before selection for Chandra observations. Sent email to the group.
Jan.24, 2012
We had astrostatistics meeting today. The first meeting after the winter break. Vika described the problem we plan to work on this semester. It is a detection of a break in the spectrum with upper limits. Alex sent a list of papers to consider for the stats method. Most importantly Xiao-Li said that this is an interesting statistics problem and worth considering. Vika will do some reading and I need to start looking at the data.
Exciting!
I also decided to rerun all the fits and update the table in the paper to include abundance information.
Runs not take too much time. I just needed to update the scripts.
Exciting!
I also decided to rerun all the fits and update the table in the paper to include abundance information.
Runs not take too much time. I just needed to update the scripts.
Jan. 23, 2012
Had a meeting with a potential summer student and discussed projects related to Chandra.
March 15, the Chandra proposal deadline is getting closer. I decided to go ahead and submit a notice of intent for the X-ray Very Large project on jets. A final decision on the observational strategy is going to be tough, but the initial plan is to engage the team in the conversation next week. This week is devoted to the EVLA proposal and John is leading it.
Malgosia is working on a final draft of the paper describing the X-ray properties of the nucleus of our radio galaxy. The analysis are done! The issues related to IR emission and dusty torus we have been discussing over the last few weeks are still unresolved. We need more IR data from the nucleus to learn more on this, so the current paper is going to be focused on the X-ray properties. The Chandra results are new, showing some details of the absorbed AGN with surprising X-ray luminosity given the strong, extended radio structure.
Jan. 22, 2012 - Research Notes
In old days researchers recorded their work in notebooks, diaries or journals. Now we have computers and some of us keep records on hard drives or internet blogs. The modern way...
I am entering the new era and plan to record my research days here in this blog.
Not much happened today, because it is Sunday, but I still think about issues of metal abundances in hot medium of the radio galaxy I observed with Chandra. Most of the ISM in this galaxy shows extreme, close to zero values and only the central regions have abundances close to Solar or even higher than the Solar. Yesterday I rerun fitting code and got the final numbers for the paper.
Last week was the Fermi proposal deadline. On Friday Giulia finished and submitted the proposal for a small sample of quasars to study their gamma-ray properties and SEDs.
I am entering the new era and plan to record my research days here in this blog.
Not much happened today, because it is Sunday, but I still think about issues of metal abundances in hot medium of the radio galaxy I observed with Chandra. Most of the ISM in this galaxy shows extreme, close to zero values and only the central regions have abundances close to Solar or even higher than the Solar. Yesterday I rerun fitting code and got the final numbers for the paper.
Last week was the Fermi proposal deadline. On Friday Giulia finished and submitted the proposal for a small sample of quasars to study their gamma-ray properties and SEDs.
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