PROGRAMA FONDECYT INFORME FINAL ETAPA 2017 COMISIÓN NACIONAL DE INVESTIGACION CIENTÍFICA Y TECNOLÓGICA VERSION OFICIAL Nº 2 FECHA: 30/10/2017 Nº PROYECTO : 3150238 DURACIÓN : 3 años AÑO ETAPA : 2017 TÍTULO PROYECTO : AN EXTINCTION-FREE VIEW OF STAR FORMING GALAXIES AND THEIR CONSTITUENTS THROUGH RADIO AND MM/SUB-MM OBSERVATIONS. DISCIPLINA PRINCIPAL : ASTRONOMIA GRUPO DE ESTUDIO : ASTRON.,COSMOL.Y PAR INVESTIGADOR(A) RESPONSABLE : CRISTINA ROMERO CAÑIZALES DIRECCIÓN : COMUNA : CIUDAD : Santiago REGIÓN : METROPOLITANA FONDO NACIONAL DE DESARROLLO CIENTIFICO Y TECNOLOGICO (FONDECYT) Moneda 1375, Santiago de Chile - casilla 297-V, Santiago 21 Telefono: 2435 4350 FAX 2365 4435 Email: [email protected] INFORME FINAL PROYECTO FONDECYT POSTDOCTORADO OBJETIVOS Cumplimiento de los Objetivos planteados en la etapa final, o pendientes de cumplir. Recuerde que en esta sección debe referirse a objetivos desarrollados, NO listar actividades desarrolladas. Nº OBJETIVOS CUMPLIMIENTO FUNDAMENTO 1 Exploiting high-resolution radio data to obtain an TOTAL I participated in different ISI publications extinction-free view of the star formation and contributing with the analysis and/ or AGN activity in starbursting systems. interpretation of proposed and/or archival radio observations of different galaxies which have undergone or are undergoing a merger and thus contain star-formation and AGN components. The references are Koss et al. (2015), Ricci et al. (2016), Romero-Cañizales et al. (2016) and Romero-Cañizales et al. (2017). 2 mm/sub-mm studies of the gas and dust in a rare PARCIAL The publication I am leading based on ALMA triple merger, to shed light into the star formation observations is still in preparation. New ALMA processes and the active phase of AGN in and VLA data were obtained within the past three extreme environments. years. This added needed components to our work but have turned it at the same time more complex. I expect to complete this work in the next few months and publish it during the first half of 2018. However, one article containing part of our study has already been submitted and accepted in an ISI journal (see Väisänen et al. 2017). I also participated in two publications studying the mm-continuum in dusty star-forming galaxies at high-redshift (see details in González-López et al. 2017 and Laporte et al. 2017). 3 Constraining the circumstellar medium around TOTAL I participated in different ISI publications related young CCSNe in starburst galaxies with radio and to the study of core-collapse supernovae and a mm-wavelength studies to help us characterize "new" class of transient which has risen great the progenitor stars and aid in the understanding interest in the last few years (tidal disruption of the different CCSN types. events). In some cases the transients have shown signatures expected from TDEs but also from supernovae, making their interpretation more challenging. I contributed with proposed and/or archival radio observations (analysis and/or interpretation) and also as an observer at the New Technology Telescope in La Silla in the studies published by Kangas et al. (2016), Dwarkadas et al. (2016), Leloudas et al. (2016), Kool et al. (2017), Bose et al. (2017) and Kankare et al. (2017). Otro(s) aspecto(s) que Ud. considere importante(s) en la evaluación del cumplimiento de objetivos planteados en la propuesta original o en las modificaciones autorizadas por los Consejos. RESULTS OBTAINED: For each specific goal, describe or summarize the results obtained. Relate each one to work already published and/or manuscripts submitted. In the Annex section include additional information deemed pertinent and relevant to the evaluation process. The maximum length for this section is 5 pages. (Arial or Verdana, font size 10). My FONDECYT postdoctoral project aimed at offering a more comprehensive view of galaxies which undergo a period of very active star formation probably accompanied by super-massive 6 9.5 black hole (SMBH; MBH=10 – 10 M⊙) growth and subsequent active galactic nucleus (AGN) activity. These galaxies are usually interacting systems whose energy is mostly emitted in the IR 11 with a luminosity above 10 L⊙ (Kilerci-Eser, Goto, Doi 2014), and therefore receive the name of luminous infrared galaxy (LIRG), or ultra luminous infrared galaxy (ULIRG) if its luminosity 12 surpasses 10 L⊙. The research objectives of the project were: 1) Exploiting high-resolution radio data to obtain an extinction-free view of the star formation and AGN activity in starbursting systems. 2) mm/sub-mm studies of the gas and dust in a rare triple merger, to shed light into the star formation processes and the active phase of AGN in extreme environments. 3) Constraining the circumstellar medium (CSM) around young core-collapse supernovae (CCSNe) in starburst galaxies with radio and mm-wavelength studies to help us characterize the progenitor stars and aid in the understanding of the different CCSN types. In the following, I describe the results pertaining to each research objective. Research objective 1 is an effort to build a sample of (U)LIRGs observed with radio interferometry techniques and help understand their powering mechanisms and evolution. The most significant result I obtained in the context of this research objective comes from the study of the LIRG IC883. This is an advanced merger in which the star formation dominates the global energetics of the system. However, our radio observations show that the nuclear region is dominated by an AGN that has a core-jet morphology (see Figure 1). The core has a very inverted spectrum and a low frequency turnover at ~4.4 GHz, indicating this is a young source (~3000 yr). These and other properties, make of IC883 a candidate for the nearest, the least luminous and one of the youngest Gigahertz-Peaked Spectrum (GPS) sources ever found. It has been proved in the past that there is a relation between merging galaxies and GPS sources, however, finding them in very active star- forming environments is very uncommon. Our study has opened a new window to investigate the physical environments of low-luminosity, young GPS sources, which can potentially be a numerous population among LIRGs in an advanced merger stage, but have so far been missed presumably owing to the lack of high-resolution, high-sensitivity radio data (see more details in Romero- Cañizales et al. 2017). The Luminous InfraRed Galaxy Inventory (LIRGI; http://lirgi.iaa.es/) is a high-resolution radio complement to legacy observations made with the NASA Great Observatories All-Sky LIRG Survey (GOALS) program. It includes e-MERLIN and EVN continuum, line (HI, OH) as well as polarisation observations. Although I expected these data to be ready during my FONDECYT postdoctoral project, the observations have been suffering from multiple delays and only a handful from the 42 galaxies have been observed. During a visit I made to the Jodrell Bank Centre for Astrophysics in 2016, I worked on the e-MERLIN data of galaxy Mrk 331. The continuum data did not have a high- enough signal to noise ratio and it only shows a compact source, likely the nucleus of the galaxy, and some hints of diffuse emission. Unfortunately the HI and OH line data were not useful and we are still waiting for new observations to be delivered. As an extension of this research objective, I also studied PGC043234, a post-starburst galaxy that resulted from a merger (Prieto et al. 2016) and has currently a negligible star formation. This system recently hosted the tidal disruption event (TDE) ASASSN-14li. TDEs are one of the mechanisms able to alter the accretion rate of material onto a SMBH, by means of the total or partial disruption of a star that wanders in the vicinity of the BH (e.g., Evans et al. 1989). Either at an early or at a late merger stage, a galaxy providing material for the steady or intermittent accretion onto a BH will also be the scenario for the formation of a jet. The host galaxy can be dusty and have large amounts of gas (e.g., a LIRG) or an over-density of stars (e.g., post- starburst galaxy) hence making most observations of the innermost <100 pc region (where the activity is taking place) basically infeasible. Our EVN observations of ASASSN-14li have allowed us to resolve the system into two components 2pc apart (see Figure 2). The components resemble a core-jet/outflow system, whose secondary component can be related directly to ASASSN-14li if its motion is superluminal, or to a past AGN or TDE if its motion is subluminal. The exiting possibility exists that both components are instead a binary BH system. We have been granted more EVN and global VLBI time which will help characterise these components and understand their origin (see more details in Romero-Cañizales et al. 2016). Related to this research objective, I also participated in the following studies: * NGC 3393 is a spiral galaxy with negligible star formation and a Seyfert 2 nucleus. In the past, it was reported to be the host of a dual AGN, the one with the smallest physical separation ever found (150 pc; Fabbiano et al. 2011). The aftermath of a galaxy merger is a powerful AGN, and thus, the detection of dual AGNs represent a test for the merger-driven AGN model. However, only a few cases of dual AGN at sub-kiloparsec separations have been confirmed. NGC 3393 not being an obvious present nor past merger, was an outstanding case and represented a challenge to the formation of powerful AGNs. I studied archival radio data from the VLA and VLBA and found that the large scale structure resembles an AGN with a two-sided jet rather than a dual AGN. This work, together with a re-analysis of archival X-ray and other data showed that the previously claimed detection of a dual AGN in this galaxy was indeed spurious.