The key responsibilities of the leadership role:
Contributing to and implementing a vision
Discussing and agreeing direction
Building trust and inspiring teamwork
Fostering high performance
Anticipating and implementing change
Influencing, enabling and empowering others
Setting and providing guidance on values
Stimulating innovation and enterprise
Anticipating, planning for and leading change
Communicating and motivating
Supporting and developing programmes, projects, teams and individuals
Modelling appropriate behaviour
Representing the team and feeding back its experiences and views
Protecting the team and its members (where appropriate)
Being open to the idea that you do not have every 'right' answer
The Merriam-Webster Dictionary defines being responsible as being "liable to be called to account."
As a leader you are responsible for the things go well or not within your team. Even when someone else may have made a mistake, you are likely to be held accountable.
This is mainly because it is your responsibility to know what your team are doing and how. There can be a competition with your desire to trust and empower your team to do things and the need to know what is happening.
It is useful to hold in mind that whilst the benefits of trust and empowerment are clear, you are still responsible if things do not go according to plan.
This may be a challenge for the new leader as you establish what to question and what to let happen.
It is important that you allow some to time to understand the role of the team and what they are trying to achieve. It is important to avoid an temptation to blame others, regardless of whether you are new or not.
This does not mean that people get away with mistakes or inappropriate working. They should be held to account but with you and by focusing on the development. "What would you differently if you did this over again?" is a very different question to "Why did you do that?" Accountability should be about what to do again or not to do in the future. (This of course depends on the severity of the action. Gross misconduct may come with more severe consequences).
Be aware when you are trying to place the blame at others feet.
Be honest with yourself and with others.
Respond to others blame appropriately.