The 4th joint meeting of eBOSS-DESI France

4 oct. 2018, 09:00 → 5 oct. 2018, 17:00 Europe/Paris

Marseille

The Centre de Physique des Particules de Marseille (CPPM) and the Laboratoire d'Astrophysique de Marseille (LAM) are very pleased to be hosting the eBOSS-DESI France meeting for its 4th edition.

One of the goals of these series of informal eBOSS-DESI meetings is to put in contact researchers working in similar topics within eBOSS and DESI collaborations.

 

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NEW: A visit to the Winlight company based in Pertuis is scheduled on Thursday 4th morning (an arrival at the Aix-en-Provence TGV rail-station is required between 9:30 and 10am). Please register soon if you want to participate (limited places).

The collaboration meeting will start on Thursday 4th at 2pm at the LAM (Chateau-Gombert campus). It will continue on Friday, October 5th at the CPPM (Luminy campus).

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Please register if you plan to attend and submit a title and an abstract if you aim to give a talk.

We encourage PhD and Postdocs to present their on-going work.

We hope to see you soon in Marseille,

The organizers.

jeudi 4 octobre

14:00 → 17:00 LAM Day

In Mistral meeting room on 2nd floor

14:00 Observations in Cosmology

In the era of upcoming redshift surveys, the sky will be more revealing than ever! In this talk, I will summarise standard and non standard observational methods and scenarios.

Orateur: Pierros Ntelis (CPPM)

14:20 DT-Voids and BAO

Status of work

Orateur: Mme Charling Tao (CPPM)

14:40 Study of the void related systematics in the Alcock-Paczynski test

The Alcock-Paczynski test is a very simple yet powerful tool to constraint cosmology when applied to voids. In this talk, I will present preliminary work accomplished in order to master void related systematics in the Alcock-Paczynski test.

Orateur: Marie Aubert (CPPM)

15:00 Coffee break

15:30 Measuring the growth rate of structure with cosmic voids in GAMA

We measure the cross correlation of voids and galaxies in the Galaxy And Mass Assembly (GAMA) survey. This cross correlation exhibits an anisotropy indicative of redshift space distortions (RSD) caused by galaxies falling from the centres of voids onto the surrounding mass. We introduce a model for the multipoles of the void-galaxy cross correlation function that allows for void positions to be subject to RSD themselves. We fit this model to the data and measure the growth rate parameter associated with galaxies, $\beta_g=0.481^{+0.049}_{-0.048}$, finding no strong evidence for void motions.

I will also present some plans for voids in the eBOSS/DES overlap.

Orateur: Dr Adam Hawken (CPPM)

15:50 DESxeBOSS gravity test discussion

In this session, I will briefly mention my plans for this project, and try to set up a schedule for the analysis.

Orateur: Eric Jullo (LAM)

16:10 Quasar identification with SQUEzE

We present the current performance of the machine-learning code, SQUEzE, to identify quasars and estimate their redshift. We compare its performance with that of QuasarNet and conclude that, while it may not be as accurate as QuasarNet, it is lighter and more flexible

Orateur: Ignasi Pérez-Ràfols (LAM, Marseille)

vendredi 5 octobre

10:00 → 13:00 CPPM Day

In the CPPM amphitheatre

10:00 Measurment of the BAO with Lya auto and cross correlation functions

I will present the current status of the Lya group

Orateur: Mme victoria de sainte agathe (LPNHE)

10:20 Measuring Large-Scale Inhomogeneities of Metals

We are measuring the large scale of inhomogeneity of metals, which are expected to be associated with large scale proximity to quasars. These inhomogeneities are currently traced by combining oxygen, helium and hydrogen absorption, but in the future they will refer to directly observed quasar positions.

Orateur: Sean Morrison (LAM)

10:40 DLA bias as a function of DLA properties

I am going to present the latest measurements of the DLA bias. In particular I'll present its evolution with redshift, column density of the DLAs, and the metal strength of the DLAs. The metal strength is defined from an average of equivalent widths of the strongest detectable low-ionization metal lines. These results confirm the physical origin of the relation of bias factors measured from cross-correlation studies to the host halos of the absorbers.

Orateur: Ignasi Pérez-Ràfols (LAM, Marseille)

11:00 Coffee break

11:30 The Study of Galaxies in Absorption and their use as a tracer.

I will discuss latest results on the properties of galaxies traced by the strong Lyman-alpha forest absorption and, on combining them with Damped Lyman alpha forest absorbers, their use as a BAO tracer.

Orateur: Matthew Pieri (Laboratoire d'Astrophysique de Marseille)

11:50 1D power spectrum from Lya forest with eBOSS quasars

Presentation of the analysis of the 1D power spectrum from the lyman alpha forest with DR14

Orateur: Solène Chabanier (CEA Saclay)

12:10 eBOSS-DESI France Planning Discussion