Hi, I don't know how to react to a situation. So what has happened is that I just graduated as PhD in physics. Without going into much details, I did measurements that gave OK results but it was possible that the measurements can be improved because there was some difficulties.

My time as funded PhD was coming to an end and that the department was moving to a new place. I started working on my writing, and focusing on finishing the PhD. A postdoc took over the work. The department moved so the postdoc have been working on re-establishing the lab and rebuilding the setups (and even improving some parts of the setup). This has been completed now the postdoc is working on the project, doing measurements.

I have been hired for a short time and will be working under the postdoc on the project. What took me by surprise was that I was told by the supervisor that the postdoc was going to be first author on the article that will be produced for the work. I was kind of surprised since this is based on my work and I been working on getting the result for along time. His argue is that the postdoc will write the article, and they are doing new measurements. Therefore the postdoc should be first author.

Is this something I shouldn't be worried about? It doesn't feel good since this was my final paper. I will still be co-author. i don't like confrontation so I guess there isn't much I can do about it. My supervisor mentioned I could submit my work to photonics west conference and attend present it next year. I'm just wondering if such things matter? I have a few first author paper (nothing super important, novel suff), one co-author(which is par of the work) and this was suppose to be my final one.

Different labs have different protocols for this. As a postdoc, I have submitted abstracts to conferences as first author even though none of the work was mine at all, but my supervisor told me to do this as I would be carrying on with some of the work.

There is some valid argument about the person that will be writing the paper and submitting to the journal should be first author, since this takes a lot of time (as I'm sure you know).

And today, a PhD student in their 4th year has decided not to continue with the experiments to finish the work needed for another paper, so my supervisor said if I finish this last bit off, I can be first author. Pretty unfair if you ask me, but then the student has had the opportunity to do it so...

I think it is the norm. That person will be putting in loads of work and making it publishable. You could try talking openly about it to see if something can be negotiated - like you do it instead.